Exhibit 99.1

NEWS For Immediate Release

Editorial Contact: Erin Jones

949-754-8032

erin.jones@quest.com

Investor Contact: Scott Davidson

949-754-8659

scott.davidson@quest.com

QUEST SOFTWARE REPORTS REVENUE AND EARNINGS FOR

FOURTH QUARTER AND FISCAL YEAR 2005

Company Posts $476 Million In Revenue for Fiscal 2005;

Fourth Quarter Revenue Grows 23%

ALISO VIEJO, Calif., February 8, 2006 – Quest Software, Inc. (Nasdaq: QSFT), a leading provider of application, database and infrastructure management solutions, today reported financial results for the fourth quarter and fiscal year ended December 31, 2005. Total revenues increased 23% year-over-year to $144.6 million in the fourth quarter of 2005 compared to last year’s fourth quarter revenue of $118.1 million. Total revenues increased 22% to $476.4 million in fiscal 2005 compared to total revenues of $389.5 million in fiscal 2004.

GAAP Results

Quest Software’s GAAP net income for the fourth quarter was $16.1 million, or $0.16 per diluted share. The GAAP operating margin was 20% in the fourth quarter, resulting in GAAP operating income of $28.9 million. Net income for the full year ended December 31, 2005 was $41.8 million or $0.41 per diluted share versus net income of $47.2 million or $0.48 per diluted share for the comparable period in 2004. Operating income for fiscal 2005 was $74.1 million, a 16% increase over the same period in 2004. Quest Software generated cash flow from operations of $43.6 million in the December 2005 quarter. During the fourth quarter of 2005, Quest Software incurred a charge of $2.3 million for income taxes arising from the repatriation of approximately $43.5 million of accumulated income earned abroad, pursuant to the American Jobs Creation Act.

Non-GAAP Results

On a pro forma basis, net income for the fourth quarter 2005 was $21.2 million or $0.21 per diluted share. The pro forma operating margin was 24% for the fourth quarter, resulting in pro-forma operating income of $35.2 million. Pro forma net income for fiscal 2005 was $64.5 million, a 22% increase over the prior year and resulting in $0.64 per diluted share. Pro forma operating income for fiscal 2005 was $103.4 million, a 43% increase over fiscal 2004.

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Quest Reports Fourth Quarter and Fiscal 2005 Results – page 2 of 9

A reconciliation of pro forma and as reported financial results is included with this press release.

“We ended 2005 with strong financial and operating results for the fourth quarter and the full year,” said Vinny Smith, chairman and chief executive officer, Quest Software. “Our innovative products are helping customers get more performance, productivity, availability and value from their applications, databases and infrastructure. We are continuing to invest in our business to gain market share and grow, and I am excited about our prospects for 2006.”

Quest Software management utilizes non-GAAP financial measures in the presentation of the Company’s results to provide a consistent understanding of its historical operating performance and comparisons with peer companies. Management believes that pro forma reporting provides a more meaningful representation of the Company’s on-going economic performance and therefore uses pro forma reporting internally to evaluate and manage the Company’s operations. Management believes that these measures provide useful information because they exclude certain items including amortization of acquisition-related intangible assets, other compensation expenses associated with stock options, litigation-related loss contingency reserves and impacts of other events, which might otherwise obscure the results of operations of our core business when compared to our historical performance or competitors or are not necessarily relevant to understanding the operating activities within the Company’s business.

Financial Outlook

Quest Software management offers the following guidance for the quarter ending March 31, 2006:

• Revenue is expected to be in the range of $117 million to $120 million.

• GAAP diluted earnings per share is expected to be in the range of $0.03 to $0.05 per share. Our GAAP guidance excludes amortization of intangible assets, potential in-process research and

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Quest Reports Fourth Quarter and Fiscal 2005 Results – page 3 of 9

development charges, and the related impacts on our tax rate, arising from our January 2006 acquisition of AfterMail Limited, which are not available at the present time;

• Pro forma diluted earnings per share is expected to be in the range of $0.11 to $0.13 per share. The pro forma guidance excludes approximately $0.03 per share of amortization of acquisition-related intangible assets and $0.05 per share related to the effects of stock-based compensation expense.

For the full year ending December 31, 2006, Quest Software management offers the following guidance:

• Annual revenue is expected to be in the range of $525 million to $540 million;

• GAAP diluted earnings per share is expected to be in the range of $0.33 to $0.39 per share. Our GAAP guidance excludes amortization of intangible assets, potential in-process research and development charges, and the related impacts on our tax rate, arising from our January 2006 acquisition of AfterMail Limited, which are not available at the present time;

• Pro forma diluted earnings per share is expected to be in the range of $0.67 to $0.72. The pro-forma guidance excludes approximately $0.13 per share of amortization of acquisition-related intangible assets and $0.20 to $0.21 per share related to the effects of stock-based compensation expense.

Fourth Quarter and Fiscal 2005 Conference Call Information

Quest Software will host a conference call today, Wednesday, February 8, 2006 at 2:00 p.m. Pacific Time, to discuss its results. A simultaneous Web cast of the conference call will be available on Quest Software’s Web site in the Investors – IR Events section at www.quest.com. A Web cast replay will be available on the same Web site through February 8, 2007. An audio replay of the call will also be available through February 22, 2006 by dialing (888) 203-1112 (from the U.S. or Canada) or (719) 457-0820 (outside the U.S. and Canada), using confirmation code: 7303184.

About Quest Software, Inc.

Quest Software, Inc. delivers innovative products that help organizations get more performance and productivity from their applications, databases and infrastructure. Through a deep expertise in IT operations and a continued focus on what works best, Quest helps more than 18,000 customers worldwide meet higher expectations for enterprise IT. Quest Software can be found in offices around the globe and at www.quest.com.

Quest and Quest Software are registered trademarks of Quest Software, Inc. The Quest Software logo and all other Quest Software product or service names and slogans are registered trademarks or trademarks of Quest Software, Inc. All other trademarks and registered trademarks are property of their respective owners.

Quest Reports Fourth Quarter and Fiscal 2005 Results – page 4 of 9

Forward Looking Statements

This release and the matters to be discussed on the conference call may include predictions, estimates and other information that might be considered forward-looking statements, including statements relating to expectations of growth, revenues, operating efficiencies and earnings per share in future periods. These statements are based on current expectations and assumptions that are subject to risks and uncertainties. Actual results could differ from those anticipated as a result of various factors, including: the impact of adverse changes in general economic conditions on our customers; reductions or delays in information technology spending; variations in the size and timing of customer orders; competitive products and pricing; rapid technological change; risks associated with the development and market acceptance of new or enhanced products; the effects of FAS 123(R) on our GAAP operating expenses due to the variability of the factors used to estimate the value of stock-based compensation; disruptions caused by acquisitions of companies and/or technologies and the integration of acquired products, services, employees and operations; fluctuating currency exchange rates and other risks associated with international operations; and the need to attract and retain qualified employees. For a discussion of these and other related risks, please refer to our recent SEC filings, including our Annual Report on Form 10-K for the year ended December 31, 2004 and our Quarterly Report on Form 10-Q for the period ended September 30, 2005, which are available on the SEC’s website at www.sec.gov. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date thereof. We undertake no obligation to update forward-looking statements to reflect events or circumstances after the date thereof.

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Quest Reports Fourth Quarter and Fiscal 2005 Results – page 5 of 9

QUEST SOFTWARE, INC.

CONSOLIDATED INCOME STATEMENTS

(In thousands, except per share data)

(Unaudited)

	Three Months Ended December 31,					Twelve Months Ended December 31,
	2005			2004		2005			2004
Revenues:
Licenses	$	85,504		$	73,269	$	260,349		$	225,032
Services		59,128			44,781		216,033			164,431
Total revenues		144,632			118,050		476,382			389,463
Cost of revenues:
Licenses		1,693			1,123		5,004			3,958
Services		11,285			7,907		38,128			29,646
Amortization of purchased technology		3,151			2,126		10,910			8,107
Total cost of revenues		16,129			11,156		54,042			41,711
Gross profit		128,503			106,894		422,340			347,752
Operating expenses:
Sales and marketing		60,306			50,510		200,335			170,702
Research and development		23,896			19,924		87,876			78,305
General and administrative		13,282			10,833		45,034			36,493
Amortization of other purchased intangible assets		2,222			1,351		7,179			5,212
In-process research and development		(110	)		—		7,840			6,980
Litigation loss contingency		—			11,000		—			16,000
Total operating expenses		99,596			93,618		348,264			313,692
Gain on sale of Vista Plus product suite		—			—		—			29,574
Income from operations		28,907			13,276		74,076			63,634
Other income (expense), net		84			6,093		(1,634	)		8,976
Income before income tax provision		28,991			19,369		72,442			72,610
Income tax provision		12,864			6,106		30,644			25,390
Net income	$	16,127		$	13,263	$	41,798		$	47,220
Net income per share:
Basic	$	0.16		$	0.14	$	0.43		$	0.50
Diluted	$	0.16		$	0.13	$	0.41		$	0.48
Weighted average shares:
Basic		99,211			95,557		97,621			94,622
Diluted		102,680			99,635		100,770			98,158

Quest Reports Fourth Quarter and Fiscal 2005 Results – page 6 of 9

QUEST SOFTWARE, INC.

CONSOLIDATED INCOME STATEMENTS

(In thousands, except per share data)

(Unaudited)

	Three Months Ended December 31, 2005							Twelve Months Ended December 31, 2005
	GAAP			Adjustments		Adjusted		GAAP			Adjustments		Adjusted
Revenues:
Licenses	$	85,504				$	85,504	$	260,349				$	260,349
Services		59,128					59,128		216,033					216,033
Total revenues		144,632					144,632		476,382					476,382
Cost of revenues:
Licenses		1,693		(1	)(1)		1,692		5,004		(1	)(1)		5,003
Services		11,285		(51	)(1)		11,234		38,128		(197	)(1)		37,931
Amortization of purchased technology		3,151		(3,151	)		—		10,910		(10,910	)		—
Total cost of revenues		16,129					12,926		54,042					42,934
Gross profit		128,503					131,706		422,340					433,448
Operating expenses:
Sales and marketing		60,306		(320	)(1)		59,986		200,335		(1,374	)(1)		198,961
Research and development		23,896		(573	)(1)		23,323		87,876		(1,655	)(1)		86,221
General and administrative		13,282		(78	)(1)		13,204		45,034		(187	)(1)		44,847
Amortization of other purchased intangible assets		2,222		(2,222	)		—		7,179		(7,179	)		—
In-process research and development		(110	)	110	(2)		—		7,840		(7,840	)(3)		—
Total operating expenses		99,596					96,513		348,264					330,029
Income from operations		28,907					35,193		74,076					103,419
Other income (expense), net		84					84		(1,634	)				(1,634	)
Income before income tax provision		28,991					35,277		72,442					101,785
Income tax provision		12,864		1,166	(4)		14,030		30,644		6,630	(4)		37,274
Net income	$	16,127				$	21,247	$	41,798				$	64,511
Net income per share:
Basic	$	0.16				$	0.21	$	0.43				$	0.66
Diluted	$	0.16				$	0.21	$	0.41				$	0.64
Weighted average shares:
Basic		99,211					99,211		97,621					97,621
Diluted		102,680					102,680		100,770					100,770

(1) Represents stock-based compensation and payroll taxes attributed to stock option exercises.

(2) Represents a purchase price allocation adjustment to Vintela, Inc.’s in-process research and development charge.

(3) Represents a one-time charge to write off in-process research and development assumed with our acquisitions of Wingra Technologies, Inc. in January 2005 and Vintela, Inc. in July 2005.

(4) Represents the related tax effects of all adjustments and the tax provision related to the repatriation of foreign earnings under the American Jobs Creation Act.

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Quest Reports Fourth Quarter and Fiscal 2005 Results – page 7 of 9

QUEST SOFTWARE, INC.

CONSOLIDATED INCOME STATEMENTS

(In thousands, except per share data)

(Unaudited)

	Three Months Ended December 31, 2004						Twelve Months Ended December 31, 2004
	GAAP		Adjustments		Adjusted		GAAP		Adjustments		Adjusted
Revenues:
Licenses	$	73,269			$	73,269	$	225,032			$	225,032
Services		44,781				44,781		164,431				164,431
Total revenues		118,050				118,050		389,463				389,463
Cost of revenues:
Licenses		1,123				1,123		3,958				3,958
Services		7,907	(45	)(1)		7,862		29,646	(190	)(1)		29,456
Amortization of purchased technology		2,126	(2,126	)		—		8,107	(8,107	)		—
Total cost of revenues		11,156				8,985		41,711				33,414
Gross profit		106,894				109,065		347,752				356,049
Operating expenses:
Sales and marketing		50,510	(379	)(1)		50,131		170,702	(1,409	)(1)		169,293
Research and development		19,924	(219	)(1)		19,705		78,305	(569	)(1)		77,736
General and administrative		10,833	(19	)(1)		10,814		36,493	(40	)(1)		36,453
Amortization of other purchased intangible assets		1,351	(1,351	)		—		5,212	(5,212	)		—
In-process research and development		—	—			—		6,980	(6,980	)(2)		—
Litigation loss contingency		11,000	(11,000	)(3)		—		16,000	(16,000	)(3)		—
Total operating expenses		93,618				80,650		313,692				283,482
Gain on sale of Vista Plus product suite		—				—		29,574	(29,574	)		—
Income from operations		13,276				28,415		63,634				72,567
Other income, net		6,093				6,093		8,976				8,976
Income before income tax provision		19,369				34,508		72,610				81,543
Income tax provision		6,106	5,600	(4)		11,706		25,390	3,248	(4)		28,638
Net income	$	13,263			$	22,802	$	47,220			$	52,905
Net income per share:
Basic	$	0.14			$	0.24	$	0.50			$	0.56
Diluted	$	0.13			$	0.23	$	0.48			$	0.54
Weighted average shares:
Basic		95,557				95,557		94,622				94,622
Diluted		99,635				99,635		98,158				98,158

(1) Represents stock-based compensation and payroll taxes attributed to stock option exercises.

(2) Represents one-time charges to write off in-process research and development assumed with our acquisition of Aelita Software in March 2004 and Lecco Technology in April 2004.

(3) Represents a special charge for a loss contingency reserve related to our Computer Associates intellectual property litigation.

(4) Represents the tax effect of all adjustments.

Quest Reports Fourth Quarter and Fiscal 2005 Results – page 8 of 9

QUEST SOFTWARE, INC.

CONSOLIDATED BALANCE SHEETS

(In thousands)

(Unaudited)

	December 31, 2005		December 31, 2004
ASSETS
Current assets:
Cash and cash equivalents	$	121,025	$	118,157
Short-term marketable securities available for sale		74,398		15,892
Accounts receivable, net		116,052		98,800
Prepaid expenses and other current assets		15,202		12,528
Deferred income taxes		10,623		13,075
Total current assets		337,300		258,452
Property and equipment, net		82,845		52,761
Long-term marketable securities		47,538		163,527
Amortizing intangible assets, net		68,975		41,404
Goodwill		428,418		323,903
Other assets		4,828		3,304
Total assets	$	969,904	$	843,351
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	3,756	$	4,135
Obligation under repurchase agreement		—		12,632
Accrued compensation		32,696		27,802
Other accrued expenses		34,351		46,292
Income taxes payable		18,300		12,030
Current portion of deferred revenue		140,267		106,356
Total current liabilities		229,370		209,247
Long-term liabilities:
Long-term portion of deferred revenue		34,980		20,897
Deferred income taxes		9,294		4,526
Other long-term liabilities		1,460		1,769
Total long-term liabilities		45,734		27,192
Shareholders’ equity		694,800		606,912
Total liabilities and shareholders’ equity	$	969,904	$	843,351

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Quest Reports Fourth Quarter and Fiscal 2005 Results – page 9 of 9

QUEST SOFTWARE, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

(Unaudited)

	Three Months Ended December 31,						Twelve Months Ended December 31,
	2005			2004			2005			2004
Cash flows from operating activities:
Net income	$	16,127		$	13,263		$	41,798		$	47,220
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		9,728			5,860			30,734			26,420
Compensation expense associated with stock option grants		898			512			2,930			1,778
Deferred income taxes		(777	)		6,702			(834	)		7,314
Gain on sale of Vista Plus product suite		—			—			(39	)		(29,574	)
Tax benefit related to stock option exercises		1,125			1,112			6,060			3,909
Provision for bad debts		187			124			264			236
In-process research and development		(110	)		—			7,840			6,980
Litigation loss provision		—			11,000			—			16,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable		(31,001	)		(28,220	)		(20,519	)		(34,290	)
Prepaid expenses and other current assets		(4,615	)		(1,196	)		(5,616	)		(1,472	)
Other assets		(518	)		4,246			(1,468	)		3,870
Accounts payable		1,035			(1,531	)		(1,045	)		(829	)
Accrued compensation		6,772			5,706			4,879			7,747
Other accrued expenses		6,697			2,349			2,590			(3,285	)
Litigation settlement payment		—			—			(16,000	)		—
Income taxes payable		8,317			(7,344	)		7,706			2,619
Deferred revenue		29,828			25,617			43,976			41,371
Other liabilities		(110	)		(216	)		(1,343	)		92
Net cash provided by operating activities		43,583			37,984			101,913			96,106
Cash flows from investing activities:
Purchases of property and equipment		(6,875	)		(3,863	)		(41,109	)		(31,873	)
Cash paid for acquisitions, net of cash acquired		(5,316	)		(369	)		(120,621	)		(96,733	)
Proceeds from sale of Vista Plus product suite		—			—			2,039			22,515
Purchases of marketable securities		—			(9,994	)		—			(10,001	)
Sales and maturities of marketable securities		1,290			12,948			56,272			40,446
Net cash used in investing activities		(10,901	)		(1,278	)		(103,419	)		(75,646	)
Cash flows from financing activities:
Proceeds from repurchase agreement		—			—			10,008			67,581
Repayment of repurchase agreement		(10,171	)		(14,980	)		(22,896	)		(55,492	)
Repayment of notes payable		—			—			(51	)		(769	)
Repayment of capital lease obligations		(54	)		(125	)		(324	)		(400	)
Proceeds from the exercise of stock options		6,148			9,676			13,295			16,704
Proceeds from employee stock purchase plan		—			—			—			4,797
Net cash provided by (used in) financing activities		(4,077	)		(5,429	)		32			32,421
Effect of exchange rate changes on cash and cash equivalents		1,664			(2,504	)		4,342			(2,194	)
Net increase in cash and cash equivalents		30,269			28,773			2,868			50,687
Cash and cash equivalents, beginning of period		90,756			89,384			118,157			67,470
Cash and cash equivalents, end of period	$	121,025		$	118,157		$	121,025		$	118,157