Thomas H. Carolan, 73, an attorney specializing in international law in Washington and in Maryland for the past 34 years, died Saturday at his Chevy Chase home after a heart attack.

A native of Ridgeway, Iowa, Mr. Carolan was a special assistant attorney general of Iowa before moving to this area in 1942 to work for the Treasury Department. He served in the general counsel's office at the Treasury Department until 1946, when he established a private law practice here and in Maryland.

One of the most noteworthy cases was a recovery suit involving assets of Japanese investors frozen by the government during World War II.

The precedent-setting suit resulted in the recovery of $6.3 million on behalf of 1,800 Japanese investors.

Mr. Carolan graduated from Loras College in Dubuque, Iowa, and earned a law degree from Georgetown University.

He was a member of the board of directors and secretary of the Montgomery Federal Savings and Loan Association and a former chairman of the D.C. International Law Committee.

He was a former vice chairman of the Montgomery County Democrats, a member of the Friendly Sons of St. Patrick and a former grand knight of Rock Creek Council of the Knights of Columbus, where he had achieved the fourth degree.

Survivors include his wife of 49 years, the former Margaret McConnell of Chevy Chase; two sons, Thomas, of Bethesda, and Michael, of Chevy Chase; two daughters, Mary Byrne Callahan of Atlanta and Ann Carolan of Brooklyn, N.Y., 16 grandchildren and one great-granddaughter.