The National Institute of Mental Health Diagnostic Interview Schedule (NIMH-DIS) was administered by trained lay interviewers to a sample of 82 outpatients with clinical diagnoses of DSM-III schizophrenic disorder. Of these subjects, 77 percent were also diagnosed as suffering from DSM-III schizophrenic disorder according to the structured interview (NIMH-DIS) administered by a lay interviewer. The DIS interviews were scrutinized to find the reasons for their discrepancy with the clinical diagnoses. A majority of the DIS-negative schizophrenic subjects acknowledged significant psychopathology in the DIS and missed only one of the six DSM-III criteria items for schizophrenia. Test-retest results showed consistency in the subjects' reporting of lifetime schizophrenic symptoms.