Alfred D. Buchmueller, 68, who was deputy executive director of the President's Committee on Mental Retardation, died Sunday at Fairfax Hospital after a heart attack.

He joined the committee in 1971 as a program specialist dealing with problems in early childhood development, international programs, environmental influences and minority affairs. He was named deputy executive director in 1977.

Before joining the committee, he served as director of the Children's Mental Health Project in New York, sponsored by the National Institute of Mental Health.

Mr. Buchmueller then was executive director of the Child Study Association of America from 1957 to 1969. The association was a nonprofit research organization on child development and parent-child relations.

He was a native of Minonk, Ill. He earned bachelor's degrees from Elmhurst College and Eden Seminary in Webster Groves, Mo., and a master's degree in social work from Washington University in St. Louis.

Mr. Buchmueller served on the staff of the psychiatry department of Washington University's medical school for 18 years before moving to New York.

He was a member of the board of directors of the St. Louis Nursery Foundation, one of the early integrated nursery schools in that region.

He directed the mental health service of the St. Louis County Health Department from 1951 to 1957.

Mr. Buchmueller was a charter member of the National Association of Social Work and a fellow of the American Orthopsychiatric Association.

He belonged to St. Christopher's Episcopal Church in Springfield, Va.

He is survived by his wife, Genevieve, of the home in Springfield; a son, Donald, of Monmouth Beach, N.J.; two daughters, Judy Hahn, of South Orange, N.J., and Marcia Cameron, of Manchester, Mich.; two brothers, the Rev. H.C. Buchmueller, of Walpole, Mass., and the Rev. O. H. Buchmueller, of Minneapolis, and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the National Association for Retarded Citizens in Arlington, Tex.