Middle-aged women with schizophrenia and two matched control groups drawn from a similar hospital environment and a normal population were tested for autoantibodies to nuclear, thyroid, gastric, smooth muscle, and mitochondrial antigens. Schizophrenic patients failed to show the association of antibodies considered to be characteristic of autoimmune disease. In the schizophrenic patients and hospitalized subnormal controls there was an increased prevalence of autoantibodies to nuclei of blood polymorphonuclear leukocytes. This could be attributed to chance or an effect associated with prolonged hospitalization. Our findings offer little support to the autoimmune concept of schizophrenia.