Robert E. von Otto, 62, a mechanical engineer who was a partner in the Washington mechanical and electrial engineering consulting firm of von Otto & Bilecky, died of cancer Oct. 2 at his home in Washington.

Mr. von Otto was born in Connecticut. He graduated from George Washington University in 1941 and served in the Army Air Forces during World War II.

After the war, he worked briefly for the U.S. Maritime Commission and then joined the General Services Administration. He rose to the GSA's national chief of engineering and held that post when he retired in 1962.

When he left the government, Mr. von Otto went into private industry. He formed the partnership of von Otto & Bilecky in June of this year.

Mr. von Otto was a member of the American Society of Heating, Refrigerating & Air Conditioning Engineers, the American Consulting Engineers Council, the Washington Metropolitan Board of Trade and the Mayor's Building Code Advisory Committee. He served on the advisory board of the Columbia First Federal Savings & Loan Association and was an usher at the Washington Cathedral.

Survivors include his wife, Mary Eloise of Washington; his father, Harold L. Otto of Westport, Conn.; his mother, Catherine Otto of Melbourne, Fla., and a brother, Donald W. Otto of Brewster, N.Y.