Roscoe Lynn Egger Jr., 79, an Internal Revenue Service commissioner during the Reagan administration, died after heart surgery Oct. 14 at the Mayo Clinic. He lived in Green Valley, Ariz.

Mr. Egger, a partner in the national accounting firm Price Waterhouse before and after his IRS service, headed the agency during one of its rockiest periods. IRS computers were unable to cope with the increase in the number of filings, and a deficit-conscious Congress changed the tax codes four times.

Problems hit a peak in 1985, when the IRS lost millions of returns and took far longer to process refunds than in the past. There were widespread computer foul-ups and news reports of occasional incidents of tampering or destruction of returns.

A General Accounting Office investigation found that IRS computer systems were woefully out of date and poorly maintained.

Mr. Egger responded by increasing computer hardware capacity by up to 50 percent at some service centers and boosting the number of central computers in operation across the country.

In 1986, he helped draft a tax reform act that helped simplify the tax codes, the last time that was accomplished by national legislation.

The IRS continued to be plagued with processing problems after he left office in 1986, however. In a 1990 interview, Mr. Egger noted that the system still being used to review returns was "an old batch-processing system that prevents online inquiries" and made it "impossible to identify a return on an individual basis." The system needed to be changed from the ground up, he said.

Mr. Egger was a native of Jackson, Mich., and a graduate of Indiana University. He received a law degree from George Washington University after serving in the Army in Europe during World War II. He received a Bronze Star and a Purple Heart.

He began his career with the GAO and was in private practice before joining Price Waterhouse. He retired there in 1990.

Mr. Egger was chairman of the board of National Cathedral School for Girls and Wolf Trap Associates, a director of the U.S. Chamber of Commerce and the Chesapeake Bay Maritime Museum and a member of St. Alban's Episcopal Church in Washington, the Commission on Administrative Review of the House of Representatives, the American Institute of Certified Public Accountants and the American and D.C. bar associations.

His marriage to Patricia Egger ended in divorce.

Survivors include his wife, Betty Slattery Egger of Green Valley; two children from his first marriage; three stepchildren; and seven grandchildren.