Gloria Askew Thomas, 55, a statistical assistant for the Census Bureau and a community leader in civic and civil rights affairs, died of cardiac arrest Tuesday at Greater Southeast Community Hospital.

Mrs. Thomas, who was born in Ashevill, N.C., served as a WAC with the 477th Bombardment Group in this country during World War II.

She and her husband, William Maurice Thomas, an analyst for the Bradford National Corp. in Rockville, lived in New York City before moving to Washington in 1950.

A census taker for the 1960 national census, she joined the Census Bureau in 1968 as a statistical assistant in the income branch of the population division.

In 1954, Mrs. Thomas helped establish a YWCA field activity in the Fort DuPont-Stoddert community, where she was known for her work with youth. She also served as an officer of the Fort DuPont-Stoddert Civic Association.

After moving to Chapel Hill in Prince George's County in 1962, Mrs. Thomas became active in Girl Scout and 4-H work. She was a leader in Fellowship for Equal Rights activities in Prince George's County in the mid-1960s.

Mrs. Thomas was instrumental in developing the Emmanuel Mansfield Scholarship Fund at Grace United Methodist Church in Chapel Hill.

Besides her husband, of Chapel Hill, survivors include three daughters, Rosa, of Cambridge, Mass., and Patricia and Helen, and two sons, Maurice III, and Hugh, all of Chapel Hill, and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Emmanuel Mansfield Scholarship Fund at Grace United Methodist Church in Chapel Hill.