Clarence M. McMillan, 75, a retired trade association executive who was active in church, civic and charitable organizations, died of cardiac arrest Friday in his home in College Park.

Mr. McMillan was executive vice president and chief executive officer of the National Candy Wholesalers Association for 25 years before retiring in 1970. He had served on the association's advisory council of past presidents since that time.

He had been a director of the American Society of Association Executives and had served on the board of managers of the National Institutes for Organization Management.

An area resident since 1945 and longtime resident of College Park, he had been a vice president of the College Park Citizens Association. He was named Rotarian of the Year by the College Park Rotary Club one year and he had chaired the Prince George's County chapter of the American Red Cross.

He was an elder of the Riverdale Presbyterian Church in University Park, where he had served as sessions clerk, chaired the church memorial committee, and been active in the church's drive for Cambodian relief funds.

Mr. McMillan was a native of Florida and had been a trade association official in Atlanta before coming to Washington.

Survivors include his wife, Lenore of College Park; two sons, Clarence M. Jr., also of College Park, and Jay Gardner McMillan of Alexandria; a daughter, Dinah Kahler of Denver, Colo., and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Heart Association of Prince George's County, the American Red Cross of Prince George's County, or the McMillan Memorial Fund of the Riverdale Presbyterian Church in University Park.