Joseph Rosa, 74, a retired Foreign Service officer in the State Department who specialized in economics and economic assistance programs, died of cancer Friday at George Washington University Hospital.

Mr. Rosa was born in Hungary of American citizens and came to the United States as a youth.He lived in Madison, Wis., and did undergraduate and graduate work in economics and political science at the University of Wisconsin. He had maintained a home in Washington since 1939.

He began his government career as an economist in the Bureau of Agricultural Economics in the Department of Agriculture. After three years of Army service in World War II, he was named head of the finance section of the U. S. element of the Allied Occupation Commission for Austria.

After returning to Washington, Mr. Rosa was assigned to the Bureau of Economic Affairs in the State Department and worked on the Marshall Plan and other foreign assistance programs.

He joined the Foreign Service in 1956. His assignments abroad included the U.S. Embassy in Paris, where he was deputy chief for economic analysis, South Vietnam, where he was chief of the embassy economic section, and South Korea, where he was counsellor for economic affairs in the embassy. His last year in government were back at State, where he was in the Office of International Scientific and Technological Affairs.

Mr. Rosa retired in 1966 and spent the next 10 years as a private consultant on international finance and development.

He was a member of the International Club of Washington, the Cosmos Club, the National Economists Club, the American Foreign Service Association, the American Association for the Advancement of Science, the American Political Science Association and the American Economic Association.

Survivors include his wife, the former Frances McConnell, of Washington, and a brother, Andor, of Passaic, N.J.

The family suggests that expressions of sympathy be in the form of contributions to the DACOR Educational & Welfare Foundation, 1718 H. St. NW, Washington, D. C.