OBJECTIVE In the last several decades, considerable evidence has suggested that autism and schizophrenia are unrelated. However, recent reports have suggested that individuals with autism may be at greater risk for schizophrenia and that the conditions may be more closely related than generally believed. METHOD The authors examined detailed case records of 163 adolescents and adults with well-documented histories of autism. These cases included 139 males and 24 females. RESULTS Only one individual had an unequivocal history of schizophrenia. CONCLUSIONS If the present study group is taken to be representative, it appears that the frequency of schizophrenia among autistic patients (0.6%) is roughly comparable to the frequency of schizophrenia in the general population. It does not appear that the two conditions are more commonly observed together than would be expected on a chance basis; therefore, the current (DSM-III-R) approach to dual diagnosis of these conditions appears reasonable.