Objective: Despite the discovery of new antipsychotic drugs, a number of schizophrenic patients show no response to such drugs and are considered treatment-resistant. In such cases, clozapine and occasionally ECT or a combination of drugs are used, though they are not very effective. In recent years, the combination of clozapine and ECT for treatment-resistant schizophrenic patients has been suggested; the results of preliminary studies have been hopeful. The aim of this study was to compare the results of treatment with clozapine alone, ECT alone, and the combination of clozapine with ECT in treatment-resistant schizophrenia.Methods: Eighteen treatment-resistant schizophrenic patients were assigned to three equal groups: one group was given clozapine; one group was treated with ECT; and one group was treated with the combination of clozapine and ECT. The treatment response was evaluated using the PANSS criteria, and the data were analyzed with ANOVA.Results: Combination therapy was superior to single modality therapy. The reduction of PANSS scores was 46% in the clozapine group, 40% in the ECT groups, and 71% in the combination group; the difference between the combination group and the other groups was statistically significant (P<0.05). Patients had a quick response to combination treatment, which resulted in a higher cure rate of positive and negative symptoms and improved the patients’ general performance. There were no significant adverse effects with combination treatment.Conclusion: Combination treatment with clozapine and ECT was safe and effective in treatment-resistant schizophrenic patients. It should be considered for the treatment of treatment-resistant schizophrenic patients.