John W. Byrnes, 71, a Wisconsin Republican who spent 28 years in the House of Representatives where he became ranking member of the powerful Ways and Means Committee, died Jan. 12 at a hospital in Marshfield, Wis., after a stroke.

A resident of Arlington, he was in Wisconsin for treatment of an unrelated medical ailment when he was stricken.

At the time of his retirement from the House in 1973, he was its top Republican authority on tax and trade matters. He became a member of Ways and Means in 1947, and Congress passed few bills dealing with taxes, trade, and Social Security that did not bear his conservative mark.

He also had chaired the House Republican Policy Committee from 1959 to 1965, had chaired his state's House delegation for many years, and served on the Joint Congressional Committee on Internal Revenue Taxation.

In 1949, he was a founder of the Chowder and Marching Club, an informal organization of younger House Republicans. Other members included his friend and Wisconsin colleague, Melvin R. Laird (who later served as Defense Secretary) and two future presidents of the United States, Gerald R. Ford and Richard M. Nixon. Mr. Byrnes was instrumental in the election of Ford as House Republican leader in 1965. Mr. Byrnes was Wisconsin's favorite son at the 1964 Republican National Convention.

Long considered one of the brightest members of Congress, Mr. Byrnes owed his considerable power mainly to his intellectual leadership of the Republicans on Ways and Means, the committee that wrote much of the most important economic legislation after World War II. From the time he entered Congress in 1945, he had generally concentrated on efforts to persuade Congress to spend less money, reduce the national debt, and slow the growth of the federal government. Yet, he was no hard-line ideologue.

Indeed, it was his ability to compromise with former representative Wilbur Mills (D-Ark.), the longtime chairman of Ways and Means, and to deliver the other Republican votes in committee that made much legislation possible. A skillful debater, he also was about the only Republican who could occasionally better Mills in floor debate on the complex issues with which Ways and Means dealt.

Mr. Byrnes and Mills served together on Ways and Means for a quarter of a century. They collaborated to enact Medicare in 1965, and to oppose the revenue-sharing package originally submitted by the Nixon administration. When the two were united, they seldom failed.

Political scientist John F. Manley, in a 1970 book on Ways and Means, said that "Mills and Byrnes together, not just Mills alone, are responsible for the way the committee goes about its business. Far from being cut off from influence in the committee, the Republicans feel that because of Mills and Byrnes they have as much say if not more than the Democrats."

During those years, bills generally left the committee under closed rules stipulating that no amendments could be made from the House floor, and the House rarely voted against the wishes of the committee.

If work done by Mr. Byrnes and the committee lacked headline-grabbing excitement, it did not lack importance. He was a major proponent of President Nixon's Family Assistance Plan of 1970. He introduced the 1954 Customs Simplification Act, helped write the 1954 Internal Revenue Code revision, and cosponsored the 1960 Kerr-Mills act, a health-care measure.

Although he supported the 1965 Medicare bill, he voiced concern that its financing through Social Security would destroy the financial foundation of that system. He opposed general revenue sharing, seemingly one of the few bills concerning taxation he opposed that became law.

Since leaving the House, he had been affiliated with the Washington office of the Milwaukee law firm of Foley and Lardner.

John William Byrnes was born June 12, 1913, in Green Bay, Wis. He was a 1936 graduate of the University of Wisconsin and earned his law degree there in 1938. For the next three years, he served as special deputy banking commissioner for the state of Wisconsin. He was elected to the state Senate in 1940, and served as its Judiciary Committee chairman and a year as majority floor leader, before winning election to the House of Representatives in 1944.

That year, he defeated incumbent Rep. LaVern R. Dilweg (D-Wis.) and a Progressive Party candidate. His district, the old 8th, covered the northeast portion of the state. Though it included the cities of Green Bay and Appleton, it was largely rural but included some lumbering.

A Green Bay journalist summed up Mr. Byrnes' appeal to the voters when he wrote, "Perhaps his real importance in the public life in his era is that he has shown that a conservative can be respected, and popular, and cumulatively more successful at the ballot box, if he combines a conservative inclination with intelligence and courage."

Survivors include his wife, the former Barbara Preston, whom he married in 1947, and three daughters, Barbara Peritore, and Bonnie Jean and Elizabeth Byrnes, all of Arlington; three sons, John W., of Madison, Wis., Michael P., of Chicago, and Charles K., of Fairfax; a brother, William, of Michigan; a sister, Betty Liebl of Wisconsin, and two grandchildren.