L. Noble Robinson, 75, retired associate executive editor of the U.S. News and World Report, died Monday at the Washington Hospital Center of complications from pneumonia.

Mr. Robinson was brought to Washington in 1939 by David Lawrence to help change the weekly newspaper, United States News, into the magazine format which eventually became U.S. News and World Report.

He reported on finance, business and Latin American affairs and served for many years as assistant to the executive editor before retiring in 1970.

In 1937, Mr. Robinson helped in the establishment of Look magazine and remained as an editor there until coming to Washington.

He was born in Salt Lake City. After graduating from the University of Michigan in 1927, he worked for two newspapers in Butte, Mont., and then for the Salt Lake Tribune, where he was city editor and wrote a "News of the Week in Review" feature.

Mr. Robinson, who lived in Washington, had been a member of the National Press Club since 1939. He belonged to the International Club and Friends of the National Zoo.

He is survived by his wife, Barbara Gray Robinson of Washington; three sons, Prentiss N., of Los Angeles, Worden, of sperryville, Va., and Sherman, of Washington; two sisters, Peggy Dick of Massachusetts, and Edith Worden Long of La Jolla, Calif., and five grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to Children's Hospital.