During the summer of 1938, detailed studies were made of the molts of the Northern Yellow-throat, Geothlypis trichas brachidactyla, in southern Michigan. Observations of the post-natal molt were made each day on nestlings found near Geddes Pond, one mile east of Ann Arbor. Studies of the post-juvenal and post-nuptial molts were from fresh specimens collected at Portage Lake in Jackson County.