The short- and long-term treatment tolerance of low-dose clozapine was retrospectively investigated in 18 psychogeriatric patients. Discontinued use of the drug because of side effects or inefficiency was required for only four patients. In the long-term treatment group leukopenia was not observed, and disturbances of liver function appeared to be very infrequent. A second group of seven severely demented psychogeriatric inpatients who were currently being treated with low-dose clozapine underwent a withdrawal study in order to evaluate the therapeutic efficacy of the drug, measured by the NOSIE and the SCAG scales. The results indicate that for patients such as these, with paranoid or socially disturbing behavior who also tend to develop severe neurological side effects with classical neuroleptics, a low-dose administration of clozapine is an acceptable alternative treatment.