FOR IMMEDIATE RELEASE

For more information, contact:

Kevin Eichner (314) 725 5500

Frank Sanfilippo (314) 725 5500

Melissa Sturges (816) 235 7733

ENTERPRISE FINANCIAL REPORTS 47.4% INCREASE IN EARNINGS

PER SHARE OVER PREVIOUS YEAR

Trust And Financial Advisory Income Grows 43.1%

St. Louis, October 20, 2003 – Enterprise Financial Services Corp. (OTCBB: EFSC), the parent company of Enterprise Bank and Enterprise Trust reported record third quarter net income of $1.8 million or $0.18 per fully diluted share and $5.5 million or $0.56 per fully diluted share for the nine months ended September 30, 2003. The reported earnings per fully diluted share for the three months ended September 30, 2003 represent a 28.6% increase over the same period in 2002. For the nine-month year to date period, the increase is 47.4%.

“The performance of our noninterest income generators and our ability to hold margins in our core banking business in this environment have been significant contributors to our earnings momentum,” said Kevin Eichner, President and CEO of Enterprise Financial.

Portfolio loans grew by 9.6% or $66 million since December 31, 2002 and ended the quarter at $745 million. This growth was funded in part by increases of $42 million or 5.8% in deposits for the same period. Net interest income for the nine months ended September 30, 2003 was $24.4 million, a $1.5 million or 6.6% increase over the same period last year. During the nine months ended September 30, 2003, the net interest rate margin increased to 4.06% from 4.05% for the same period last year.

Total noninterest income grew by $4,422,000 for the nine months ended September 30, 2003 versus the same period in 2002. This increase was generated from a $3,088,000 gain on the sale of three branches in April less a $150,000 write-off of related goodwill, higher gains on the sale of mortgage loans of $705,000 and increased trust and financial advisory income of $745,000. Mortgage gains grew by 67.6% and trust and financial advisory income grew by 43.1%. Assets under management in Enterprise Trust were $1.04 billion at September 30, 2003 versus $866 million at September 30, 2002, a 20% increase. Enterprise Trust remains one of the fastest growing trust companies in the United States.

The provision for loan losses was $2,728,000 for the nine months ended September 30, 2003 compared to $1,760,000 for the same period in 2002. This increase reflects management’s cautionary view of the economic environment as the company continues its strong loan growth. The allowance for loan losses of $10.1 million at September 30, 2003 represents 1.35% of ending portfolio loans. This same ratio was 1.27% at December 31, 2002.

Expense ratios continued to improve as reduced staffing levels, productivity increases, and business process improvements were implemented. The efficiency ratio improved from 72.15% for the nine months ended September 30, 2002 to 65.70% for the same period in 2003.

“Enterprise is building a strong core earnings base at accelerating rates. The addition of outstanding new talent in our banking business such as Steve Marsh (former President at Southwest Bank in St. Louis), the continued rapid advance of our wealth management units, and our margin and expense initiatives are combining as we had planned to significantly improve our performance,” 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, 2003 and December 31, 2002 and consolidated statements of operations for the three and nine months ended September 30, 2003 and 2002 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 2002 Annual Report on Form 10-K.

ENTERPRISE FINANCIAL SERVICES CORP AND SUBSIDIARIES

Consolidated Balance Sheets (unaudited)

(Dollars in thousands, except per share data)

	September 30, 2003		December 31, 2002
Assets
Cash and due from banks	$	30,774	$	39,052
Federal funds sold		9,271		33,367
Interest-bearing deposits		562		66
Investments in debt and equity securities:
Available for sale, at estimated fair value		61,442		66,619
Held to maturity, at amortized cost (estimated fair value of $11 at September 30, 2003 and $13 at December 31, 2002)		11		13
Total investments in debt and equity securities		61,453		66,632
Loans held for sale		3,357		6,991
Loans, less unearned loan fees		745,330		679,799
Less allowance for loan losses		10,070		8,600
Loans, net		735,260		671,199
Other real estate owned		—		125
Fixed assets, net		7,278		7,686
Accrued interest receivable		3,236		3,459
Goodwill		1,938		2,088
Assets held for sale		—		36,401
Prepaid expenses and other assets		10,191		9,721
Total assets	$	863,320	$	876,787
Liabilities and Shareholders’ Equity
Deposits:
Demand		155,567		155,597
Interest-bearing transaction accounts		49,262		59,058
Money market accounts		356,693		341,590
Savings		4,539		3,421
Certificates of deposit:
$100,000 and over		146,931		105,030
Other		44,973		51,618
Total deposits		757,965		716,314
Guaranteed preferred beneficial interests in subordinated debentures		15,000		15,000
Federal Home Loan Bank advances		17,677		29,464
Notes payable and other borrowings		1,887		2,359
Accrued interest payable		1,192		1,264
Liabilities held for sale		—		50,054
Accounts payable and accrued expenses		5,171		3,522
Total liabilities		798,892		817,977
Shareholders’ equity:
Common stock, $.01 par value; authorized 20,000,000 shares; issued and outstanding 9,592,296 shares at September 30, 2003 and 9,497,794 shares at December 31, 2002		96		95
Surplus		39,535		38,401
Retained earnings		23,589		18,674
Accumulated other comprehensive income		1,208		1,640
Total shareholders’ equity		64,428		58,810
Total liabilities and shareholders’ equity	$	863,320	$	876,787

ENTERPRISE FINANCIAL SERVICES CORP AND SUBSIDIARIES

Consolidated Statements of Operations (unaudited)

(Dollars in thousands, except per share data)

	Three months ended September 30,				Nine months ended September 30,
	2003		2002		2003		2002
Interest income:	$	10,297	$	11,014	$	30,972	$	32,440
Interest and fees on loans
Interest on debt and equity securities:
Taxable		363		330		1,252		1,148
Nontaxable		9		—		13		1
Interest on federal funds sold		26		164		112		291
Interest on interest-bearing deposits		2		5		2		28
Dividends on equity securities		20		16		53		43
Total interest income		10,717		11,529		32,404		33,951
Interest expense:
Interest-bearing transaction accounts		34		70		136		207
Money market accounts		776		1,308		2,588		3,795
Savings		3		22		21		65
Certificates of deposit:
$100,000 and over		763		782		2,172		2,400
Other		326		784		1,267		3,057
Guaranteed preferred beneficial interests in subordinated debentures expense		307		315		924		837
Federal Home Loan Bank borrowings		247		263		849		625
Notes Payable and other borrowings		6		11		35		74
Total interest expense		2,462		3,555		7,992		11,060
Net interest income		8,255		7,974		24,412		22,891
Provision for loan losses		635		640		2,728		1,760
Net interest income after provision for loan losses		7,620		7,334		21,684		21,131
Noninterest income:
Service charges on deposit accounts		455		441		1,347		1,302
Trust and financial advisory income		1,214		559		2,474		1,729
Other service charges and fee income		93		108		280		281
Gain on sale of mortgage loans		635		399		1,750		1,044
Gain on sale of securities		—		—		78		—
Gain on sale of branches		—		—		2,938		—
Recoveries from Merchant Banc investments		—		—		—		89
Total noninterest income		2,397		1,507		8,867		4,445
Noninterest expense:
Compensation		4,197		3,670		11,999		10,483
Payroll taxes and employee benefits		647		619		1,996		1,942
Occupancy		496		489		1,471		1,406
Furniture and equipment		189		246		644		753
Data processing		218		251		730		764
Other		1,508		1,449		5,025		4,375
Total noninterest expense		7,255		6,724		21,865		19,723
Income before income tax expense		2,762		2,117		8,686		5,853
Income tax expense		1,005		783		3,196		2,198
Net income	$	1,757	$	1,334	$	5,490	$	3,655
Per share amounts
Basic earnings per share	$	0.18	$	0.14	$	0.57	$	0.39
Basic weighted average common shares outstanding		9,580,091		9,444,258		9,554,540		9,381,389
Diluted earnings per share	$	0.18	$	0.14	$	0.56	$	0.38
Diluted weighted average common shares outstanding		9,880,404		9,588,205		9,861,025		9,580,300