John Clifford Folger, 84, a prominent Washington investment banker, civic leader, fund-raiser for the Republican Party and former U.S. ambassador to Belgium, died Tuesday at Georgetown University Hospital. He had a stroke.

In 1931, as the Great Depression was sliding toward its depths, Mr. Folger, who was known as "Cliff" to his friends, founded an investment banking firm called Folger, Nolan & Co. Inc. Where others failed, this enterprise prospered. It is known today as Folger, Nolan, Fleming & Douglas Inc. Because of various mergers, it is perhaps the oldest investment banking house in Washington and one of the largest. In addition to investment banking, the company is a stock brokerage. Mr. Folger remained its chairman until his death.

Among Mr. Folger's transactions in recent years was assisting Joe L. Allbritton, the noted Texas banker and entrepreneur, to buy The Washington Star Company in the early 1970s. Mr. Folger was a director of The Star until Allbritton sold the newspaper to Time Inc.

Apart from his business interests, Mr. Folger gave much of his time to civic causes. He was the general chairman of the old Community Chest drive in 1940. From 1942 to 1953, he was chairman of the D.C. chapter of the American Red Cross. It was during his terms of office that the Chapter House at 2025 E St. NW was built. He later was named chairman emeritus of the organization. He was for many years an active supporter of the Washington Cathedral, which he regarded as one of the most beautiful churches in the Western Hemisphere.

In the GOP, Mr. Folger served twice as chairman of the Republican National Finance Committee. The first time was from 1955 to 1957, when President Dwight D. Eisenhower was reelected to a second term. The second time was from 1960 to 1961, when then vice president Richard M. Nixon lost to John F. Kennedy, the Democratic nominee.

From 1957 to 1959, Mr. Folger was U.S. ambassador to Belgium. While he was there, the Brussels World's Fair was held. On his return to private life, Mr. Folger called on the World's Fair Commission to organize a similar exposition in Washington. In his address, he expressed his feelings for the city.

"I was not born in Washington," he said. "I grew up in the wild and wooly West, but I have spent my adult life here and for me -- and I think for most Americans -- Washington is the most inspirational city in the world. . . That is the factor that is so terribly important. This city belongs to all the 50 states. Gentlemen, I feel strongly and deeply this is the place where the entire country should unite and have this fair."

Mr. Folger was born in Sheldon, Iowa, on May 28, 1896, and grew up in Pullman, Wash. He earned bachelor's and master's degrees in agricultural economics at Washington State College.

In the early 1920s, he moved to Washington and went to work for the Department of Agriculture. His duties principally involved apples, an important crop in the state of Washington. Through his work at Agriculture, he came to the attention of an applegrowers association with headquarters in Rochester, N.Y. This group hired him away from the government to be its secretary.

In 1929, when the stock market, was still rising, he decided to get into the investment business. He resigned from his job in Rochester, returned to Washington and went about the task of becoming a stockbroker. Before the year was out, the market crashed with thunderous and far-reaching consequences. yThe firm where Mr. Folger worked eventually went under and he began his own business.

In the 1940s, Mr. Folger was twice elected president of the Investment Bankers Association. He was a former governor of the New York Stock Exchange. In the course of his career, he served on the boards of numerous corporations, including Virginia Industries and Piedmont Mortgage Co,, the Chesapeake & Potomac Telephone Co., Burlington Industries Corporation, IBM and Hilton Hotels. At his death, he was a member emeritus of the boards of IBM and Hilton.

Mr. Folger, who lived in Washington, was a member of the National Institute of Social Sciences, and the Alfalfa, Chevy Chase, Metropolitan and 1925 F Streets clubs. He also was a member of the New York Downtown Association and the Everglades Bath and Tennis Club in Palm Beach, Fla. a

Survivors include his wife, the former Kathrine Dulin, of Washington, and two sons, John Dulin and Lee Merritt, both also of Washington.

The family suggests that expressions of sympathy be in the form of contributions to the D.C. chapter of the American Red Cross or to Washington Cathedral.