Victor M. Mercogliano, 56, a government lawyer and administrative law judge, died of cancer Wednesday at Washington Adventist Hospital.

Since February 1978, he had been an administrative law judge for the Federal Energy Regulatory Commission. For the previous 18 years he had worked for the Civil Aeronautics Board, first as a trial lawyer and then as an assistant chief attorney in the board's economics bureau.

Mr. Mercogliano was a native of Washington and a graduate of McKinley Tech High School. He earned bachelor's and law degrees at George Washington University.

He began his government career as an attorney adviser with the D.C. Superior Court. He served in the Army Air Corps in Europe during World War II.

He was a member of the American and D.C. bar associations.

Mr. Mercogliano was a member of St. Camillus Catholic Church in Silver Spring.

Survivors include his wife, the former Gertrude McGuire, and two sons, Victor and Charles, all of the home in Silver Spring: three daughters, Nancy Yates, of Great Falls, Va., Corol, of Tallahassee, Fla., and Elizabeth, of Beltsville, and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the building fund at St. Camillus.