We report a case of idiopathic cold agglutinin disease (ICAD) that responded well to corticosteroid therapy, though generally these patients show no response to such therapy. The cold agglutinins in this patient were found to be of low titer (1:32) and wide thermal range (4-37 degrees C). Three patients with ICAD were previously reported, also responsive to corticosteroid therapy and having the same characteristics of their autoantibodies. are likely to respond to corticosteroid therapy and that a therapeutic trial with such agents is warranted in these patients.