Sera from schizophrenic patients (n = 186) and healthy control subjects (n = 346) were tested for the presence of seven common autoantibodies by standard immunological methods. The association between handedness and autoantibodies was tested in a multi-way contingency table using a log-linear model. For men, but not women, nondextrals (patients and controls) were twice as likely to test positive for autoantibodies than dextrals (p = 0.0002). Although more women (33%) than men (24%) tested positive for autoantibodies, handedness was not a distinguishing factor among women. These data suggest that sinistrality and gender are associated with autoantibodies in a subgroup of schizophrenic patients and healthy control subjects.