Background. Clozapine's effectiveness in reducing symptoms and facilitating discharge among patients with chronic schizophrenia who were resistant to neuroleptics was studied. Method. All 169 such patients in a public psychiatric hospital were given clozapine. BPRS ratings (0-5 scale) were completed before treatment and 21 months later. Patients were followed for about 2.5 years. Results. Clozapine was discontinued in 37.8% of cases due to non-compliance, non-response, or side-effects. At follow-up 41% of clozapine recipients and 25.9% of the drop-outs were discharged and remained so, and 33% of recipients and 24.1% of drop-outs were being prepared for discharge. Longer treatment was associated with more improvement. Decline in average BPRS total scores of recipients was significantly more than drop- outs (32.7, s.d. 16.8 v. 12.1, s.d. 14.1, d.f. = 155, t = 7.5, P=0.000). Conclusions. Clozapine appears to be effective for treating some chronic neuroleptic non-responding schizophrenic patients.