Sex differences with regard to age at first hospitalization and residual symptomatology were investigated in 54 long-term hospitalized chronic schizophrenics. Patients fulfilled diagnostic criteria of DSM-III, Kraepelin's dementia praecox and Leonhard's group of schizophrenias as well. The severe residual psychopathology necessitated continuous hospitalization in all the patients. The 27 women and 27 men neither differed in duration of illness or period of hospitalization nor in their social environment. We found that women were older than men at their first hospitalization and exhibited more marked positive symptomatology during the course and in the residual state than men. However, regardless of the residual symptomatology, men generally received more neuroleptics. A classification of the schizophrenic patients by means of the Leonhard criteria revealed that unsystematic schizophrenics (affect-laden paraphrenia, periodic catatonia, cataphasia) of both sexes were significantly (p less than 0.001) more often married at the time of first hospitalization than were systematic schizophrenics. Further, there was an overwhelming preponderance of women among the group of affect-laden paraphrenia and, conversely, of men in the group of periodic catatonia. Presuming different etiology in affect-laden paraphrenia and periodic catatonia, our findings suggest a significantly varied frequency in the rate in which women and men are afflicted by heterogeneous subgroups of schizophrenia.