John K. Althaus, 87, general manager and secretary-treasurer of the Credit Bureau Inc. of Washington for 31 years before his retirement in 1966, died of pneumonia Thursday at a hospital in Boulder, Colo.

Mr. Althaus was comptroller for a West Virginia department store chain and for the Jelleff stores here before joining Credit Bureau Inc. in 1935.

Under his leadership, the bureau grew from 40 to more than 300 employes and twice won the International Achievement Award from the Associated Credit Bureaus of America.

Mr. Althaus served on the board of directors and executive comittee of the Associated Credit Bureaus of America and as its president in 1964.

He was instrumental in establishing the Retail Credit Association of Metropolitan Washington, now the Consumer Credit Association, the Mutual Protective Association and the Welcome Newcomers Service.

A native of Columbus, Ohio, Mr. Althaus attended Capital University there. He moved to this area in the early 1930s and lived in Silver Spring before moving to Louisville, Colo., nine months ago.

His professional memberships included the Metropolitan Washington Board of Trade and the Washington Executives Association. He was a past director of the Kiwanis and a former president of Christ Lutheran Church of Bethesda.

Survivors include his wife, Alice W., of Louisville, Colo.; a daughter, Patricia Ann Smith of Silver Spring; two sons, Robert K., of Orlando, Fla., and Donald C., of Rockville, 16 grandchildren and 13 great-grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the American Lung Association.