Three patients are reported in whom autoimmune hemolytic anemia developed during the course of ulcerative colitis. A review of the literature yielded 11 additional cases, and the clinical, immunologic, and therapeutic characteristics are summarized. The results of steroid therapy and splenectomy are similar to those for idiopathic autoimmune hemolytic anemia. The cause and effect relationship between these two diseases is not clear, but colectomy appears to produce remission in hemolysis when the latter is refractory to both steroids and splenectomy.