Harry Venneman, 72, an economist with the statistical policy division of the Office of Management and Budget until his retirement in 1971, died of cancer Saturday at Georgetown University Hospital.

Mr. Venneman was born in St. Louis and studied library science at Washington University there. He got a degree in library science from Columbia University in New York. He became an economist while working on the "Encyclopedia of the Social Sciences" in New York.

He began his government career in 1936 as an economist with the bureau of research and statistics in the Social Security Administration. He switched to the Bureau of the Budget in 1941 and stayed with the agency when it became the OMB. He was a consultant to OMB from his retirement until 1974.

Mr. Venneman served in the Navy during World War II. One of his assignments for the Bureau of the Budget following the war was to represent the United States at the statistical office of the United Nations.

He was a member of the American Statistical Association and the American Library Association. He also was a member of the Cosmos Club.

Survivors include his wife, Dr. Natalie Deyrup Venneman, of the home in Washington; two sisters, Anne Jochens, of Kirkwood, Mo., and Johanna Ahrenhoerster, of Hartford, Wis., and three brothers, Paul, of Kirkwood, Mo., Bernard, of Kansas City, Mo., and Justin, of Saratoga, Calif.

The family suggests that expressions of sympathy be in the form of contributions in Mr. Venneman's name to the Children's Hospital, National Medical Center, Washington, D.C., 20010.