EXHIBIT 99.1

Hold for Release Until:

6:00 a.m. Eastern

May 20, 2004

Patterson Dental Company Posts Strong Fourth Quarter Operating Results

St. Paul, MN—May 20, 2004—Patterson Dental Company (Nasdaq NMS: PDCO) today reported consolidated sales of $537,359,000 for the fourth quarter of fiscal 2004 ended April 24, an increase of 20% from $447,326,000 in the year-earlier quarter. Net income increased 34% to $45,125,000 or $0.65 per diluted share, from $33,597,000 or $0.49 per diluted share in the fourth quarter of fiscal 2003. AbilityOne Products Corp., which was acquired on September 12, 2003, contributed fourth quarter earnings of $0.07 per diluted share on revenues of $57,473,000.

For full-year fiscal 2004, consolidated sales increased 19% to $1,969,349,000 from $1,656,956,000 in the prior year. Net income rose 28% to $149,465,000 or $2.17 per diluted share, from $116,320,000 or $1.70 per diluted share in fiscal 2003, before the cumulative effect of an accounting change for goodwill that resulted in a one-time, non-cash benefit of $0.05 per diluted share.

Sales of the Patterson Dental Supply unit, Patterson’s largest business, increased 8% to $426,709,000 in the fourth quarter. U.S. dental sales rose 9% for the period. All dental sales growth was generated by internal operations.

• Consumable dental supplies and printed office products increased 6% in the fourth quarter of 2004, led by U.S. consumables sales growth of 7%. The growth rate of consumable supplies accelerated during the second half of the year, reflecting the positive impact of the strengthened focus placed on this portion of Patterson’s business. Patterson’s dental sales force totaled approximately 1,350 at the end of the fourth quarter.

• Sales of dental equipment and software rose 11% in the fourth quarter, with U.S. sales increasing 12% for this period. Sales remained strong for digital radiography systems and related software, office networking hardware and such basic dental equipment as chairs, units and lights. Demand for the CEREC 3D dental restorative system also was robust during the quarter, with sales modestly exceeding the exceptionally strong level reported in the fourth quarter of 2003. Based on these results, Patterson believes dental practices are continuing to invest in a wide range of new-generation equipment designed to increase productivity and generate new revenue opportunities.

• Sales of other services and products, consisting primarily of parts, technical service, software support, and insurance e-claims, increased 13% in the fourth quarter.

Sales of the Webster Veterinary Supply unit increased 9% in the fourth quarter to $53,177,000 on a comparable basis. This excludes the impact of a temporary, pharmaceutical distribution agreement that was in place during the year-earlier quarter but was converted back into an agency commission arrangement in this year’s third quarter, as well as the April 16, 2004 acquisition of ProVet. When revenues from the distribution agreement are included in the prior year quarter and the added revenues from ProVet are factored in the current quarter results, Webster’s sales for the fourth quarter of 2004 were virtually unchanged.

Peter L. Frechette, chairman and chief executive officer, commented: “The fourth quarter was another strong period for Patterson, with all of our units generating solid operating results. To further strengthen the competitive positions and long-term prospects of our businesses, we completed a series of strategic acquisitions over the past month. ProVet, which is expected to contribute sales of $50 to $60 million in fiscal 2005, makes Webster the nation’s second largest distributor of companion-pet veterinary supplies by expanding the reach of this operation into the Midwest and Northwest. On May 3, we completed the acquisition of Medco Supply Company, Inc., a leading national distributor of sports medicine, first aid and medical supplies with sales of

approximately $40 million. Medco, which is being integrated rapidly into AbilityOne, also sells consumable supplies and equipment to podiatrists, which has been a developing customer base for AbilityOne. Then, on May 12, we completed the acquisition of CAESY Education Systems, Inc., the leading provider of electronic patient education services to dental practices in North America. CAESY’s communications media educate patients about proper dental care, procedures and treatment alternatives, with the goal of influencing patient decisions about dental services and increasing the productivity of the dental professional. This product line will equip our dental sales force with an important new value-added service. The ProVet, Medco and CAESY acquisitions are strategic in the best sense of the word, and we are confident these transactions will benefit Patterson’s performance in fiscal 2005, which we fully expect to be another year of record sales and earnings.”

For the first quarter of fiscal 2005 ending July 31, Patterson is forecasting earnings of $0.58 to $0.60 per diluted share. This guidance reflects the impact of an extra week in the first quarter of fiscal 2005, which will be a 53-week year ending on April 30, 2005. For the full year, Patterson is forecasting earnings of $2.68 to $2.72 per diluted share. The ProVet, Medco and CAESY acquisitions are expected to have a combined accretive impact of $0.04 to $0.06 on fiscal 2005 earnings, with the majority of this annual contribution forecasted during the second half of the year.

Patterson also announced that Howard A. Schwartz, president and chief executive officer of AbilityOne, has taken a medical leave of absence. Edward L. Donnelly, AbilityOne’s chief operating officer, will temporarily assume Mr. Schwartz’s responsibilities. Mr. Donnelly has been with AbilityOne and its prior owner for 10 years and has over 25 years of experience in the industry.

About Patterson Dental Company

Patterson Dental Company is a value-added distributor serving the dental, companion-pet veterinarian and rehabilitation supply markets.

Dental Market

As Patterson’s largest business, Patterson Dental Supply provides a virtually complete range of consumable dental products, equipment and software, turnkey digital solutions and value-added services to dentists and dental laboratories throughout North America.

Veterinary Market

Webster Veterinary Supply is the nation’s second largest distributor of consumable veterinary supplies, equipment, diagnostic products, vaccines and pharmaceuticals to companion-pet veterinary clinics.

Rehabilitation Market

AbilityOne Products Corp. is the world’s leading distributor of rehabilitation supplies and non-wheelchair assistive patient products to the physical and occupational therapy markets. The unit’s global customer base includes hospitals, long-term care facilities, clinics and dealers.

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This release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995. Forward-looking statements are information of a non-historical nature and are subject to risks and uncertainties that are beyond the Company’s ability to control. The Company cautions shareholders and prospective investors that the following factors, among others, may cause actual results to differ materially from those indicated by the forward-looking statements: competition within the dental, veterinary, and rehabilitative and assistive living supply industries; changes in the economics of dentistry, including reduced growth in expenditures by private dental insurance plans, the effects of economic conditions and the effects of healthcare reform, which may affect future per capita expenditures for dental services and the ability and willingness of dentists to invest in high-technology products; the effects of healthcare related legislation and regulation which may affect expenditures or reimbursements for rehabilitative and assistive products; changes in the economics of the veterinary supply market, including reduced

growth in per capita expenditures for veterinary services and reduced growth in the number of households owning pets; the ability of the Company to maintain satisfactory relationships with its sales force; unforeseen operating risks; risks associated with the dependence on manufacturers of the Company’s products; and the ability of the Company to successfully integrate the recent acquisitions into its existing business. Forward-looking statements are qualified in their entirety by the cautionary language set forth in the Company’s filings with the Securities and Exchange Commission.

For additional information contact:
R. Stephen Armstrong	Richard G. Cinquina
Executive Vice President & CFO	Equity Market Partners
651/686-1600	904/261-2210 or 800/522-1744

PATTERSON DENTAL COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME

(In thousands, except for earnings per share)

(Unaudited)

	Quarter Ended						Twelve Months Ended
	April 24, 2004			April 26, 2003			April 24, 2004			April 26, 2003
Net sales	$	537,359		$	447,326		$	1,969,349		$	1,656,956
Gross profit		200,568			155,872			702,344			574,586
Operating expenses		126,346			104,722			459,844			395,638
Operating income		74,222			51,150			242,500			178,948
Other (expense) income, net		(1,910	)		2,689			(2,980	)		7,454
Income before income taxes and cumulative effect of accounting change		72,312			53,839			239,520			186,402
Income taxes		27,187			20,242			90,055			70,082
Income before cumulative effect of accounting change		45,125			33,597			149,465			116,320
Cumulative effect of accounting change		—			—			—			3,372	(a)
Net income	$	45,125		$	33,597		$	149,465		$	119,692
Before cumulative effect of accounting change:
Earnings per share - basic	$	0.66		$	0.50		$	2.20		$	1.71
Earnings per share - diluted	$	0.65		$	0.49		$	2.17		$	1.70
After cumulative effect of accounting change:
Earnings per share - basic	$	0.66		$	0.50		$	2.20		$	1.76
Earnings per share - diluted	$	0.65		$	0.49		$	2.17		$	1.75
Shares:
Basic		68,128			67,760			67,966			67,831
Diluted		69,170			68,273			68,884			68,447
Gross margin		37.3	%		34.8	%		35.7	%		34.7	%
Operating expenses as a % of sales		23.5	%		23.4	%		23.4	%		23.9	%
Operating income as a % of sales		13.8	%		11.4	%		12.3	%		10.8	%
Effective tax rate, before cumulative effect of accounting change		37.6	%		37.6	%		37.6	%		37.6	%
Return on net sales, before cumulative effect of accounting change		8.4	%		7.5	%		7.6	%		7.0	%

(a) Due to the adoption of Financial Accounting Standards No. 142, “Goodwill and Other Intangible Assets.”

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PATTERSON DENTAL COMPANY

SUPPLEMENTARY FINANCIAL DATA

(In thousands)

(Unaudited)

	Quarter Ended						Twelve Months Ended
	April 24, 2004			April 26, 2003			April 24, 2004			April 26, 2003
Consolidated Net Sales
Consumable and printed products	$	340,772		$	279,078		$	1,235,355		$	1,044,447
Equipment and software		156,308			132,822			586,748			481,061
Other		40,279			35,426			147,246			131,448
Total	$	537,359		$	447,326		$	1,969,349		$	1,656,956
Rehabilitative Supply
Consumable and printed products	$	48,778		$	—		$	120,519		$	—
Equipment and software		8,694			—			21,237			—
Other		1			—			548			—
Total	$	57,473		$	—		$	142,304		$	—
Proforma	$	57,473		$	54,344	(a)	$	222,827	(a)	$	210,987	(a)
Veterinary Supply
Consumable and printed products	$	49,669		$	50,958		$	198,744		$	174,766
Equipment		2,389			1,564			7,293			7,714
Other		1,119			785			4,685			3,314
Total	$	53,177		$	53,307		$	210,722		$	185,794
Other Income
Interest income	$	1,549		$	2,485		$	6,312		$	7,257
Interest expense		(3,389	)		(21	)		(9,627	)		(66	)
Other		(70	)		225			335			263
	$	(1,910	)	$	2,689		$	(2,980	)	$	7,454

(a) Proforma basis, as if the acquisition had occurred at the beginning of fiscal 2003.

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PATTERSON DENTAL COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS

(Dollars in thousands)

	April 24, 2004		April 26, 2003
	(Unaudited)
ASSETS
Current assets:
Cash and short-term investments	$	295,178	$	217,448
Receivables, net		285,249		248,585
Inventory		173,022		125,340
Prepaid expenses and other current assets		24,694		14,744
Total current assets		778,143		606,117
Property and equipment, net		77,233		57,254
Goodwill and other intangible assets		698,217		135,070
Other		35,364		25,537
Total Assets	$	1,588,957	$	823,978
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	149,528	$	111,543
Other accrued liabilities		94,129		72,336
Current maturities of long-term debt		20,031		145
Total current liabilities		263,688		184,024
Long-term debt		479,556		129
Other non-current liabilities		43,955		6,139
Total liabilities		787,199		190,292
Stockholders’ equity		801,758		633,686
Total Liabilities and Stockholders’ Equity	$	1,588,957	$	823,978

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PATTERSON DENTAL COMPANY

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS

(Dollars in thousands)

(Unaudited)

	Twelve Months Ended
	April 24, 2004			April 26, 2003
Operating activities:
Income before cumulative effect of accounting change	$	149,465		$	116,320
Depreciation & amortization		19,441			12,776
Change in assets and liabilities, net of acquired		27,525			(42,353	)
Net cash provided by operating activities		196,431			86,743
Investing activities:
Additions to property and equipment, net		(19,624	)		(11,356	)
Acquisitions		(605,072	)		(6,493	)
Sale of investments		14,248			2,985
Net cash used in investing activities		(610,448	)		(14,864	)
Net cash provided by (used in) financing activities		505,995			(2,683	)
Net increase in cash and cash equivalents	$	91,978		$	69,196