Warm-reactive IgM autoimmune hemolytic anemia is uncommon and carries a poor prognosis in adults. There have been rare reports in children, generally associated with an underlying immunologic deficiency, and outcomes are quite variable. Warm IgM in combination with other antibodies has not been reported in children. We report the first case of severe, steroid-responsive autoimmune hemolytic anemia caused by both warm-reactive IgM and IgA autoantibodies in an otherwise healthy 3-month-old.