Chapman Revercomb, 84, a West Virginia Republican who twice served in the U.S. Senate, died Saturday at Kanawha Valley Hospital in Charleston, W. Va. He had pneumonia.

Mr. Revercomb was elected to the Senate in 1942 in one of the biggest political upsets in West Virginia history. He defeated Gov. Matthew M. Neely, a New Deal Democrat who was regarded as almost invincible at the polls.

In 1948, Mr. Revercomb was defeated by Neely, who by that time was a member of the House of Representatives. In 1956, Mr. Revercomb defeated outgoing Democratic Gov. William C. Marland for the final two years of the term of the term of Sen. Harley M. Kilgore, who died in office.

In 1958, Mr. Revercomb was defeated by Sen. Robert C. Byrd, now the Senate Majority leader. On hearing of Mr. Revercomb's death, Byrd said he was a "dedicated and respected U.S. senator . . . He was a friend and the state has lost a great citizen."

In all, Mr. Revercomb, a Charleston attorney, was the Republican candidate for the Senate five times.

In his first Senate term, he was known as a conservative. He advocated foreign aid cuts. He alienated labor by support for the Taft-Hartley law. He was attacked by minority and civil liberties groups as the author of what they considered an unduly restrictive law for admission to the United States of persons displaced by World War II.

Following his second election in 1956, Mr. Revercomb moved closer to the middle of the political spectrum. He was sometimes called a "liberal Republican." Among other things, he suggested abolishing the draft and relying on a professional, all volunteer army.

William Chapman Revercomb (he never used his first name in politics) was born in Covington, Va. He went to Washington and Lee University, served in the Army in World War I, and earned a law degree at the University of Virginia. He joined a law firm in Charleston, W. Va., in 1922.

He had been in failing health in recent years, plagued by two strokes and respiratory problems. But he continued to go to his office to take care of correspondence.

In addition to his wife, the former Sara Venable Hughes, of the home in Charleston, survivors include four children, Dr. William, of Charleston, George, of Washington, D.C., Anne Graney, of Mount Hope, W. Va., and James, of Roanoke Va.