EXHIBIT 99.1

For more information, contact:

Kevin Eichner (314) 725 5500

Frank Sanfilippo (314) 725 5500

Katie Hollar (816) 221 7500

ENTERPRISE FINANCIAL THIRD QUARTER EARNINGS PER SHARE

INCREASES 55.6% OVER PREVIOUS YEAR

St. Louis, October 19, 2004 – Enterprise Financial Services Corp (OTCBB: EFSC), the parent company of Enterprise Bank and Trust, reported a 55.6% increase in third quarter fully diluted earnings per share in comparison to the same quarter in 2003. Third quarter net income was $2.9 million or $0.28 per fully diluted share. Third quarter 2003 earnings were $1.8 million or $0.18 per fully diluted share.

For the nine months ended September 30, 2004, net income was $6.4 million or $0.63 per fully diluted share. For the comparable period in 2003, net income was $5.5 million or $0.56 per fully diluted share including an after tax gain from the sale of three Southeast Kansas branches which contributed $1.6 million or $0.16 per fully diluted share.

Portfolio loans at quarter end totaled $874 million. For the twelve month period ending September 30, 2004, portfolio loans grew by $129 million or 17.3%. Deposits increased $179 million or 23.6% during the same period. Loans grew by $90 million or 11.5% since December 31, 2003. The 2004 year to date loan growth was funded by a $141 million increase in deposits or 17.6% for the same period.

Net interest income increased $2.3 million or 9.4% for the first nine months of 2004 compared to the same period in 2003. The net interest rate margin through September decreased slightly from 4.06% to 3.84% primarily due to a decrease in overall loan yields.

“The Company has achieved excellent earnings momentum. This was the best quarter in the history of our Company, and we are well on the way to another record year overall. Growth in earnings per share remains our top priority while we increase our market share in both of our core lines of business,” said Kevin Eichner, president and CEO of Enterprise Financial.

The Company’s Wealth Management business segment reported total revenue growth of $549,000 or 22.2% for the first nine months of 2004 versus 2003. Total revenue for the

first nine months of 2004 was $3.0 million versus $2.5 million in 2003 Assets under administration in Enterprise Trust were $1.24 billion at September 30, 2004 versus $1.04 billion at September 30, 2003, a 19.7% increase.

Provision for loan losses in the banking segment was $1.4 million for the nine months ended September 30, 2004 compared to $2.7 million for the same period in 2003. This decline is due to stable and strong non-performing loan levels, strengthening local economies and favorable delinquency trends. The allowance for loan losses of $11.4 million at September 30, 2004 represents 1.31% of outstanding portfolio loans compared to 1.35% at December 31, 2003.

“While we are now well positioned as a growth company in the industry, we are equally gratified by the quality of our loan portfolio. This continues to be one of the hallmarks of our business,” said Eichner.

Enterprise Financial operates commercial banking and wealth management businesses in metropolitan St. Louis and Kansas City, with a primary focus on serving the needs of privately held businesses, their owners and other success-minded individuals.

Please refer to Enterprise Financial’s consolidated balance sheets as of September 30, 2004 and December 31, 2003 and consolidated statements of operations for the three and nine months ended September 30, 2004 and 2003 attached for more details.

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Readers should note that in addition to the historical information contained herein, this press release may contain forward-looking statements which are inherently subject to risks and uncertainties that could cause actual results to differ materially from those contemplated from such statements. Factors that could cause or contribute to such differences include, but are not limited to, burdens imposed by federal and state regulations of banks, credit risk, exposure to local economic conditions, risks associated with rapid increase or decrease in prevailing interest rates and competition from banks and other financial institutions, as well as those in Enterprise Financial’s 2003 Annual Report on Form 10-K.

ENTERPRISE FINANCIAL SERVICES CORP AND SUBSIDIARIES

Consolidated Balance Sheets (unaudited)

September 30, 2004 and December 31, 2003

(Dollars in thousands, except share data)

	September 30, 2004			December 31, 2003
Assets
Cash and due from banks	$	29,316		$	26,271
Federal funds sold		38,712			—
Interest-bearing deposits		142			217
Investments in debt and equity securities:
Available for sale, at estimated fair value		92,998			83,939
Held to maturity, at amortized cost (estimated fair value of $8 at September 30, 2004 and $10 at December 31, 2003)		8			10
Total investments in debt and equity securities		93,006			83,949
Loans held for sale		1,599			2,848
Loans, less unearned loan fees		874,092			783,878
Less allowance for loan losses		11,441			10,590
Loans, net		862,651			773,288
Other real estate owned		273			—
Fixed assets, net		7,071			7,318
Accrued interest receivable		3,915			3,279
Goodwill		1,938			1,938
Prepaid expenses and other assets		7,767			8,618
Total assets	$	1,046,390		$	907,726
Liabilities and Shareholders’ Equity
Deposits:
Demand	$	184,426		$	164,952
Interest-bearing transaction accounts		77,952			58,926
Money market accounts		434,678			371,583
Savings		3,992			4,123
Certificates of deposit:
$100,000 and over		190,554			154,142
Other		45,333			42,674
Total deposits		936,935			796,400
Subordinated debentures		20,619			15,464
Federal Home Loan Bank advances		11,413			14,500
Notes payable and other borrowings		430			9,647
Accrued interest payable		1,331			1,150
Accounts payable and accrued expenses		4,616			5,177
Total liabilities		975,344			842,338
Shareholders’ equity:
Common stock, $.01 par value; authorized 20,000,000 shares; issued and outstanding 9,731,990 shares at September 30, 2004 and 9,618,482 shares at December 31, 2003		97			96
Additional paid-in capital		40,653			39,841
Retained earnings		30,472			24,832
Accumulated other comprehensive (loss) income		(176	)		619
Total shareholders’ equity		71,046			65,388
Total liabilities and shareholders’ equity	$	1,046,390		$	907,726

ENTERPRISE FINANCIAL SERVICES CORP AND SUBSIDIARIES

Consolidated Statements of Operations (unaudited)

(Dollars in thousands, except share data)

	Three months ended September 30,				Nine months ended September 30,
	2004		2003		2004		2003
Interest income:
Interest and fees on loans	$	11,788	$	10,298	$	33,304	$	30,971
Interest on debt and equity securities:
Taxable		584		364		1,561		1,252
Nontaxable		10		9		31		13
Interest on federal funds sold		138		26		224		114
Dividends on equity securities		30		20		75		54
Total interest income		12,550		10,717		35,195		32,404
Interest expense:
Interest-bearing transaction accounts		97		34		194		136
Money market accounts		1,192		776		2,955		2,588
Savings		3		3		9		21
Certificates of deposit:
$100,000 and over		1,058		763		2,894		2,172
Other		259		326		778		1,267
Subordinated debentures		374		307		1,036		924
Federal Home Loan Bank borrowings		173		247		593		849
Notes payable and other borrowings		1		6		30		35
Total interest expense		3,157		2,462		8,489		7,992
Net interest income		9,393		8,255		26,706		24,412
Provision for loan losses		100		635		1,437		2,728
Net interest income after provision for loan losses		9,293		7,620		25,269		21,684
Noninterest income:
Service charges on deposit accounts		532		455		1,529		1,347
Wealth Management income		1,119		1,214		3,023		2,474
Other service charges and fee income		92		92		277		280
Gain on sale of branches		—		—		—		2,938
Gain on sale of mortgage loans		9		302		219		831
Gain on sale of securities		126		—		127		78
Total noninterest income		1,878		2,063		5,175		7,948
Noninterest expense:
Compensation		3,962		3,913		11,748		11,218
Payroll taxes and employee benefits		612		597		2,100		1,858
Occupancy		523		496		1,540		1,471
Furniture and equipment		176		189		534		644
Data processing		208		218		586		730
Other		1,575		1,508		4,547		5,026
Total noninterest expense		7,056		6,921		21,055		20,947
Income before income tax expense		4,115		2,762		9,389		8,685
Income tax expense		1,261		1,005		3,022		3,195
Net income	$	2,854	$	1,757	$	6,367	$	5,490
Per share amounts
Basic earnings per share	$	0.29	$	0.18	$	0.66	$	0.57
Basic weighted average common shares outstanding		9,723,695		9,580,091		9,681,437		9,554,540
Diluted earnings per share	$	0.28	$	0.18	$	0.63	$	0.56
Diluted weighted average common shares outstanding		10,074,329		9,880,404		10,005,663		9,861,025