Exhibit 99.1

FOR IMMEDIATE RELEASE:	FOR FURTHER INFORMATION:
Wednesday, May 24, 2006	Rich Sheffer (952) 887-3753

DONALDSON COMPANY REPORTS RECORD THIRD QUARTER RESULTS

Record third quarter EPS up 19 percent

        MINNEAPOLIS, MN (May 24, 2006) — Donaldson Company, Inc. (NYSE: DCI) today announced record third quarter diluted earnings per share (“EPS”) of $.43, up from $.36 last year. Net income was a record $37.0 million, versus $31.3 million last year. Sales were a record $429.9 million, up from $411.7 million in fiscal 2005.

        For the nine-month period, EPS was another record at $1.12, up from $.98 last year. Net income increased 12 percent to $96.1 million compared to $85.4 million last year. Sales were $1.226 billion, up 5 percent from $1.173 billion in fiscal 2005.

        “The highlight of our third quarter was our strong operating margin performance of 12.4 percent which we achieved despite continued commodity cost increases,” said Bill Cook, Donaldson’s Chairman, President and CEO. “We offset the impact of commodity cost increases through very extensive and successful cost reduction and continuous improvement initiatives across our organization. Looking forward, our outlook is good. Our open order backlog is up 19 percent supporting our guidance of a strong finish to the year and the achievement of our 17^th consecutive earnings record.”

Income Statement Discussion

        Translated at constant exchange rates, sales increased $31.2 million, or 7.6 percent, during the quarter and $82.3 million, or 7.0 percent, year-to-date. Weakening foreign currencies reduced the sales growth to $18.2 million, or 4.4 percent, in the third quarter and $53.2 million, or 4.5 percent, year-to-date. The impact of foreign currency translation decreased net earnings by $0.6 million in the third quarter and $1.1 million year-to-date.

        Gross margin of 33.5 percent and 32.7 percent for the third quarter and year-to-date compares to prior year margins of 32.5 percent and 31.6 percent, respectively. We continue to see higher costs for petroleum-based raw materials and freight being offset primarily by our cost reduction efforts and selective price increases. Third quarter operating expenses were 21.1 percent of sales, down from 22.0 percent in the prior year. Year-to-date operating expenses were 21.7 percent of sales for both year-to-date periods and the current year includes $2.6 million of stock option expense that was not included in the prior year.

        Third quarter interest expense was $2.3 million, down from $2.5 million last year due to lower short-term borrowings. Year-to-date interest expense was $7.2 million, up from $6.7 million last year. Other income was $0.9 million in the quarter, down from $1.0 million last year. Year-to-date other income was $6.2 million, down from $6.3 million last year.

        The effective tax rate of 28.6 percent for the third quarter and 27.9 percent for the year compares to 24.6 percent and 26.2 percent for the same periods in the prior year, respectively.

(more)

Donaldson Company, Inc.
May 24, 2006
Page 2

        As part of our ongoing share repurchase program, we have repurchased 745,900 shares for $25.0 million during the third quarter. Year-to-date, we repurchased 2,348,200 shares, or 2.8 percent of outstanding shares, for $73.1 million.

Backlog

        Total open order backlog is $493 million, up 19 percent relative to last year.

Engine Products Segment

        Engine Products sales were a record $258.4 million in the quarter, an increase of 6.3 percent from last year. Year-to-date Engine Products sales were a record $723.5 million, an increase of 6.4 percent from last year.

        Truck product sales in the quarter totaled $47.2 million, up 4 percent from last year. Year-to-date worldwide sales totaled $136.0 million, an increase of 5 percent from last year.

        Worldwide sales of off-road products in the quarter were $84.0 million, up 6 percent from last year, on continued global strength in new construction and mining equipment demand. Year-to-date worldwide sales totaled $225.8 million, up 7 percent from last year.

        Engine aftermarket or replacement part sales in the quarter were $127.2 million, an increase of 8 percent from last year, as equipment utilization rates remained strong. Year-to-date worldwide sales totaled $361.7 million, up 7 percent from last year.

Industrial Products Segment

        Industrial Products sales in the quarter were a record $171.4 million, an increase of 2 percent from last year. Year-to-date Industrial Products sales were a record $502.7 million, an increase of 2 percent from last year.

        Industrial Filtration Solutions (“IFS”) sales in the quarter were a record $109.2 million, an increase of 3 percent from last year. Year-to-date worldwide IFS sales totaled a record $318.9 million, up 2 percent from last year.

        Gas turbine product sales in the quarter were $26.2 million, down 7 percent from last year. Year-to-date worldwide sales totaled $78.9 million, down 3 percent from last year.

        Sales of special application products in the quarter were a record $36.0 million, an increase of 4 percent from last year. Year-to-date worldwide special application sales were a record $104.9 million, up 5 percent from last year.

Outlook

Engine Products: We expect mid- to high-single digit sales growth in fiscal 2006 and mid-single digit sales growth in fiscal 2007.

• NAFTA new heavy-duty new truck build rates should remain at their current high levels through the end of calendar 2006 as our truck manufacturer OEMs are near capacity.

(more)

Donaldson Company, Inc.
May 24, 2006
Page 3

• Strong worldwide conditions are expected to continue in the production of new construction and mining equipment by our customers.

• Both our NAFTA and international aftermarket sales are expected to continue growing with continued strong equipment utilization, continued growth by our OEM customers of their replacement parts business, and the growing amount of equipment in the field with our PowerCore™ filtration systems.

Industrial Products: We expect mid-single digit sales growth in fiscal 2006 and high-single digit sales growth in fiscal 2007.

• IFS sales are expected to continue growing with healthy industrial conditions in NAFTA and Asia, and improving industrial markets in Europe.

• Globally, we expect mid single-digit sales growth for gas turbine for the full-year. Strength is seen in both the international and the oil and gas markets.

• Market conditions for special applications products are expected to remain strong.

Other:

• On May 23, 2006, the Company’s Board of Directors approved a second foreign cash repatriation plan for an additional $80.0 million pursuant to the American Jobs Creation Act of 2004. This planned $80.0 million repatriation will result in a $3.6 million tax charge, an estimated $.04 per share, during the fourth quarter of fiscal 2006. This repatriation plan is in addition to the $80.0 million repatriation announced in July 2005.

• We expect fiscal 2006 plant rationalization and new plant start-up expenses to be $6 million to $7 million. The fourth quarter impact is expected to be $2.2 million to $3.2 million.

• We expect fiscal 2006 EPS to be in the range of $1.49 to $1.54 per share.

About Donaldson Company, Inc.

        Donaldson is a leading worldwide provider of filtration systems and replacement parts. Donaldson is a technology-driven company committed to satisfying customer needs for filtration solutions through innovative research and development. Donaldson serves customers in the diesel engine and industrial markets including in-plant air cleaning, compressed air and gas purification, power generation, disk drive filtration, off-road equipment and on-road trucks. Our 11,000 employees contribute to the company’s success at over 30 manufacturing locations around the world. Donaldson is a member of the S&P MidCap 400 Index and Donaldson shares are traded on the NYSE under the symbol DCI. Additional company information is available at www.donaldson.com.

(more)

Donaldson Company, Inc.
May 24, 2006
Page 4

SAFE HARBOR STATEMENT UNDER THE SECURITIES REFORM ACT OF 1995

        The company desires to take advantage of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995 (the “Act”) and is making this cautionary statement in connection with such safe harbor legislation. This earnings release, the Annual Report to Shareholders, any Form 10-K, 10-Q or Form 8-K of the company or any other written or oral statements made by or on behalf of the company may include forward-looking statements, forecasts and projections which reflect the company’s current views with respect to future events and financial performance but involve uncertainties that could significantly impact results. The words “believe,” “expect,” “anticipate,” “intends,” “estimate,” “forecast,” “outlook,” “plan,” “promises,” “project,” “should,” “will be” and similar expressions are intended to identify “forward-looking statements” within the meaning of the Act.

        The company wishes to caution investors that any forward-looking statements are subject to uncertainties and other risk factors that could cause actual results to differ materially from such statements, including but not limited to risks associated with: currency fluctuations, commodity prices, world economic factors, political factors, the company’s international operations, highly competitive markets, and governmental laws and regulations. For a more detailed explanation, see the Company’s 2005 Form 10-K and most recent Form 10-Q filed with the Securities and Exchange Commission. The company wishes to caution investors that new factors emerge from time to time, and it is not possible for management to predict all such factors, nor can it assess the impact of each such factor or the extent to which any factor may cause actual results to differ materially from those contained in any forward-looking statements. Investors are further cautioned not to place undue reliance on such forward-looking statements as they speak only to the company’s views as of the date the statement is made. The company undertakes no obligation to publicly update or revise any forward-looking statements.

(more)

Donaldson Company, Inc.
May 24, 2006
Page 5

CONDENSED STATEMENTS OF CONSOLIDATED EARNINGS
DONALDSON COMPANY, INC. AND SUBSIDIARIES
(Thousands of dollars, except share and per share amounts)
(Unaudited)

	Three Months Ended April 30						Nine Months Ended April 30
	2006			2005			2006			2005
Net sales	$	429,858		$	411,664		$	1,226,169		$	1,172,994
Cost of sales		285,784			277,864			825,781			802,001
Gross margin		144,074			133,800			400,388			370,993
Operating expenses		90,857			90,746			265,973			254,837
Operating income		53,217			43,054			134,415			116,156
Other income, net		(922	)		(996	)		(6,152	)		(6,281	)
Interest expense		2,302			2,470			7,235			6,734
Earnings before income taxes		51,837			41,580			133,332			115,703
Income taxes		14,825			10,247			37,213			30,260
Net earnings	$	37,012		$	31,333		$	96,119		$	85,443
Weighted average shares
outstanding		82,955,416			84,768,788			83,322,449			85,132,531
Diluted shares outstanding		85,205,858			87,103,018			85,516,497			87,465,208
Net earnings per share	$	.45		$	.37		$	1.15		$	1.00
Net earnings per share
assuming dilution	$	.43		$	.36		$	1.12		$	.98
Dividends paid per share	$	.080		$	.060		$	.240		$	.175

(more)

Donaldson Company, Inc.
May 24, 2006
Page 6

DONALDSON COMPANY, INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED BALANCE SHEETS
(Thousands of dollars)
(Unaudited)

	April 30 2006		July 31 2005
ASSETS
Cash and cash equivalents	$	72,946	$	134,066
Accounts receivable - net		302,183		294,016
Inventories - net		145,159		151,599
Prepaid expenses and other current assets		41,388		39,141
Total current assets		561,676		618,822
Other assets and deferred taxes		242,560		217,458
Property, plant and equipment - net		298,305		275,493
Total assets	$	1,102,541	$	1,111,773
LIABILITIES AND SHAREHOLDERS’ EQUITY
Trade accounts payable	$	139,975	$	134,063
Employee compensation and other liabilities		111,357		98,083
Notes payable		72,737		102,004
Income taxes payable		5,046		12,280
Current maturity long-term debt		5,718		7,772
Total current liabilities		334,833		354,202
Long-term debt		99,506		103,302
Other long-term liabilities		119,583		129,653
Total liabilities		553,922		587,157
Equity		548,619		524,616
Total liabilities and equity	$	1,102,541	$	1,111,773

(more)

Donaldson Company, Inc.
May 24, 2006
Page 7

DONALDSON COMPANY, INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
(Thousands of dollars)
(Unaudited)

	Nine Months Ended April 30
	2006			2005
OPERATING ACTIVITIES
Net earnings	$	96,119		$	85,443
Adjustments to reconcile net earnings to net cash
provided by operating activities:
Depreciation and amortization		33,800			33,494
Changes in operating assets and liabilities		9,687			(9,571	)
Payment of litigation judgment		(14,170	)		—
Tax benefit of equity plans		(12,826	)		—
Stock option expense		2,623			—
Other, net		(13,209	)		(13,440	)
Net cash provided by operating activities		102,024			95,926
INVESTING ACTIVITIES
Net expenditures on property and equipment		(48,804	)		(34,435	)
Acquisitions and investments in unconsolidated
affiliates, net of cash acquired		(4,498	)		(13,236	)
Net cash used in investing activities		(53,302	)		(47,671	)
FINANCING ACTIVITIES
Purchase of treasury stock		(73,080	)		(116,268	)
Net change in debt		(34,780	)		120,486
Dividends paid		(19,894	)		(14,775	)
Tax benefit of equity plans		12,826			—
Other, net		3,488			1,875
Net cash used in financing activities		(111,440	)		(8,682	)
Effect of exchange rate changes on cash		1,598			7,137
Increase (decrease) in cash and cash equivalents		(61,120	)		46,710
Cash and cash equivalents – beginning of year		134,066			99,504
Cash and cash equivalents – end of period	$	72,946		$	146,214

(more)

Donaldson Company, Inc.
May 24, 2006
Page 8

SEGMENT DETAIL
(Thousands of dollars)
(Unaudited)

	Engine Products		Industrial Products		Corporate & Unallocated			Total Company
3 Months Ended April 30, 2006:
Net sales	$	258,448	$	171,410		—		$	429,858
Earnings before income taxes		40,784		14,855		(3,802	)		51,837
3 Months Ended April 30, 2005:
Net sales	$	243,212	$	168,452		—		$	411,664
Earnings before income taxes		37,669		14,392		(10,481	)		41,580
9 Months Ended April 30, 2006:
Net sales	$	723,456	$	502,713		—		$	1,226,169
Earnings before income taxes		96,988		43,006		(6,662	)		133,332
9 Months Ended April 30, 2005:
Net sales	$	680,229	$	492,765		—		$	1,172,994
Earnings before income taxes		95,926		37,994		(18,217	)		115,703

NET SALES BY PRODUCT
(Thousands of dollars)
(Unaudited)

	Three Months Ended April 30				Nine Months Ended April 30
	2006		2005		2006		2005
Engine Products segment:
Off-road products	$	84,013	$	79,316	$	225,839	$	211,849
Transportation products		47,216		45,572		135,954		129,847
Aftermarket products		127,219		118,324		361,663		338,533
Total Engine Products Segment	$	258,448	$	243,212	$	723,456	$	680,229
Industrial Products segment:
Industrial filtration solutions products	$	109,238	$	105,824	$	318,881	$	311,258
Gas turbine products		26,168		27,995		78,947		81,623
Special applications products		36,004		34,633		104,885		99,884
Total Industrial Products segment	$	171,410	$	168,452	$	502,713	$	492,765
Total Company	$	429,858	$	411,664	$	1,226,169	$	1,172,994

(more)

Donaldson Company, Inc.
May 24, 2006
Page 9

RECONCILIATION OF NON-GAAP FINANCIAL MEASURES
(Thousands of dollars)
(Unaudited)

	Three Months Ended April 30						Nine Months Ended April 30
	2006			2005			2006			2005
Free cash flow	$	30,290		$	18,836		$	53,220		$	61,491
Net capital expenditures		20,193			11,914			48,804			34,435
Net cash provided by
operating activities	$	50,483		$	30,750		$	102,024		$	95,926
EBITDA	$	64,921		$	54,976		$	172,961		$	154,118
Income taxes		(14,825	)		(10,247	)		(37,213	)		(30,260	)
Interest expense (net)		(1,945	)		(1,911	)		(5,829	)		(4,921	)
Depreciation and
amortization		(11,139	)		(11,485	)		(33,800	)		(33,494	)
Net earnings	$	37,012		$	31,333		$	96,119		$	85,443
Net sales, excluding foreign
currency translation	$	442,826		$	402,774		$	1,255,252		$	1,142,253
Foreign currency translation		(12,968	)		8,890			(29,083	)		30,741
Net sales	$	429,858		$	411,664		$	1,226,169		$	1,172,994
Net earnings, excluding
foreign currency translation	$	37,627		$	30,824		$	97,186		$	83,571
Foreign currency translation		(615	)		509			(1,067	)		1,872
Net earnings	$	37,012		$	31,333		$	96,119		$	85,443

Although free cash flow, EBITDA, net sales excluding foreign currency translation and net earnings excluding foreign currency translation are not measures of financial performance under GAAP, the company believes they are useful in understanding its financial results. Free cash flow is a commonly used measure of a company’s ability to generate cash in excess of its operating needs. EBITDA is a commonly used measure of operating earnings less non-cash expenses. Both net sales and net earnings excluding foreign currency translation provide a comparable measure for understanding the operating results of the company’s foreign entities excluding the impact of foreign exchange. A shortcoming of these financial measures is that they do not reflect the company’s actual results under GAAP. Management does not intend these items to be considered in isolation or as a substitute for the related GAAP measures.

#     #     #