Mary C. Salisbury, 75, former comptroller of the Democratic National Committee for 28 years, died Saturday at Suburban Hospital in Bethesda. SHe also had served for eight years as special assistant to the director of the Mint.

Born in South Orange, N.J., Mrs.Salisbury was a graduate of Rutgers University Democratic Club, she entered politics in 1928 as a receptionist for James W. Gerard, then Democratic Party treasurer. The offices were in New York.

She later worked in Mr. Gerard's law office in Manhattan until she was appointed comptroller of the Democratic National Committee in August, 1933.

Mrs.Salisbury came to Washington in 1935, when committee offices were moved here. During her tenure as comptroller, she also served - from time to time as acting treasurer of the committee and as treasurer of a number of national conventions.

In 1961, President Kennedy appointed Mrs. Salisbury to serve as special assistant to Director of the Mint Eva Adams.

Mrs.Salisbury, who lived in Bethesda, left the Treasury in 1969, and worked on the staff of Sen. Clairborne Pell ;(D-R.I.) until she retired in 1970.

She is survived by a son, Joseph F., and a daughter, Kathryn, both of Rockville; two sisters, Theresa C.Kerber, of Stone Ridge, N.Y., and Dr.Elizabeth J.Collins, of Kingston, N.Y.; a brother, Thomas J. Collins, fo Columbia, Md., and seven grandchildren.