The charts of 168 patients with malignant melanoma were reviewed with regard to the incidence of the major blood groups. Blood group A was encountered in 39.9%, Group B in 7.7%, Group AB in 3%, and Group O in 49.4%. Although blood group O had a higher frequency compared to that of the general white population of various series, the difference was not significant. Patients with blood group A had a median survival of 67.7 months whereas patients with blood group O had a median survival of 46.6 months (p = 0.04). The improved survival for blood group A remained significant only in female patients, when the sexes were considered separately. However, group A had an incidence of 24% in early Clark's lesions while that incidence in group O was 9.8%. Female patients had longer median survival (86 months) than male patients (44 months).