Thomas DeScisciolo, 49, a member of the Arlington County School Board, died of cancer Monday at Georgetown University Hospital.

Active for many years in community and school organizations and a resident of Arlington for 25 years, he had been appointed to a four-year term on the board, which began July 1, 1976.

Mr. DeScisciolo had been assistant director of personnel for labor relations at the Treasury Department since 1974. He received the department's Meritorius Service Award this past June. He was a National Institute of Public Affairs fellow.

Members of the Arlington school board and School Supt. Larry Cuban issued statements yesterday praising Mr. DeScisciolo for his sensitivity to community relations and his belief that the quality of Arlington schools was important to the community as a whole and no just to its youngsters.

It was noted that mr. DeScisciolo was the one who suggested that the school board hold special public meetings on educational goals last Spring.

They also cited his professional expertise on personnel matters and collective bargaining as being of great value to both board members and employee associations last year in jointly working out new personnel policies. These were established after the Virginia Supreme Court ruled against collective bargaining for public service employees in the state.

Born in New York City, he received a bachelor's degree in history and economics from Queens College and a master's degree in public administration from Harvard University.

He was an officer in the Army Corps of Engineers in 1946-48.

Mr. DeScisciolo had been a personnel officer of the Bureau of Reclamation, a program planner with the Civil Service Commission and an employment officer at the Bureau of Naval Personnel.

From 1960 to 1964, he was coordinator of career programs for the Internal Revenue Service. He then served for 10 years as chief of the union relations branch at IRS.

He had been a member of the Central Arlington Schools Committee and the Arlington Committee of 100 and was a former executive board member of the Ashton Heights Civic Association.

He is survived by his wife, Cathering DeScisciolo, and two children. Stephany and Thomas, of the home; his mother, Sabina DeScisciolo, of Bayside, N.Y.; two sisters, Mary Barrow, of Little Neck. N.Y., and josephine Brady, of West Kingston, R.I., and a brother, Frank, of Huntington, N.Y.

The family suggests that expressions of sympathy may be in the form of contributions to the Vincent Lombardi Cancer Center at Georgetown Hospital.