Lansdale G. (Dee) Clagett, 70, a retired Prince George's County businessman who had represented that county as a state legislator, county commissioner and state roads commissioner during a 33-year political career, died of a heart attack Tuesday at Malcolm Grow Medical Center at Andrews Air Force Base.

Mr. Clagett, a lifelong resident of Upper Malboro, was a 20-year-old student at the University of Maryland when he contracted poliomyelitis. Although thereafter confined to a wheelchair, he was elected to the Maryland House of Delegates at age 22. He served as a Democratic delegate from 1934 to 1942, when he was elected a judge of the County Orphans Court. He remained on the bench until 1954, when he was elected to the five-member County Board of Commissioners.

In 1958, he was appointed a member of the Maryland State Roads Commission, representing Prince George's and Montgomery counties. He resigned in 1966 to run for Prince George's County commissioner and was defeated. In 1971, he also ran unsuccessfully for a seat on the County Council.

During his business career, Mr. Clagett operated two cattle farms and insurance and bonding businesses in Prince George's County. He also owned and operated the Marlboro Hardware and Supply Company in Upper Marlboro and a similar business in Aquasco before retiring in the mid-1970s.

He served as a director of the First National Bank of Southern Maryland for 30 years and was a former vice chairman of the board.

Mr. Clagett played a role in the building of Prince George's General Hospital director and chairman of the board for many years.

He also was secretary of the Marlboro Volunteer Fire Department.

Survivors include his wife, Gladys, of Upper Marlboro.

The family suggests that expressions of sympathy be in the form of contributions to the Lansdale G. Clagett Physicial Therapy Scholarship Fund, Bos 339, Upper Marlboro, Md., 20870.