Mae Helm, 39, a lawyer with the Department of Justice for more than 15 years, died of a heart ailment Friday at Georgetown University Hospital.

Miss Helm became a special assistant to the U.S. Attorney General in 1938 and later served in the antitrust and claims division before she retired in 1954.

She moved here from Kentucky in 1925 and entered into the private practice of law. In 1932 she became the first woman from Kentucky to be admitted to practice law before the U.S. Supreme Court.

From 1934 to 1938 she served as an assistant corporation counsel for the District of Columbia.

Miss Helm was born in Morgantown, Ky. She studied law in her father's office, and in 1923 passed the Kentucky bar exam and was admitted to practice law before the Kentucky Court of Appeals.

She belonged to the Daughters of the American Revolution, the Eastern Star, the Colonial Dames of America, the Descendants of the Lords of Maryland Manors, the Washington and Northern Virginia Company of the Jamestowns Society, the Kentucky Historical Society, and the Filson Club of Louisville.

She was active in several area civic organizations, especially the Metropolitan Police Boys Club. She helped found and was a past president of its women's auxiliary.

Miss Helm is survived by her sister Dixie Lyon, of Washington.

It is suggested that expressions of sympathy may be in the form of contributions to the Metropolitan Police Boys Club or the American Red Cross.