Vice President Mike Pence and relatives of the men were at Dover Air Force Base in Delaware to receive the remains.
Media representatives were on hand early Friday to witness the somber transfer of the flag-draped cases of two of the service members. The transfer of the third man was done in private.
The men were killed Tuesday by a roadside bomb in Ghazni province, where the Taliban is resurgent.
They were identified as Army Capt. Andrew Patrick Ross, of Lexington, Virginia; Army Sgt. 1st Class Eric Michael Emond, of Brush Prairie, Washington; and Air Force Staff Sgt. Dylan J. Elchin, of Hookstown, Pennsylvania.