Poor adherence to clozapine treatment represents an important problem in clinical practice because additional useful treatment options are unavailable. Although switching to risperidone long-acting injection (RLAI) has been recommended for those with compliance problems, this medication has been found to be less suitable for patients who previously received clozapine. Based on the suggested beneficial effects of RLAI, such as higher rates of treatment continuation and patient satisfaction, and the possible effectiveness of oral risperidone augmentation, it seems worthwhile to try RLAI augmentation for clozapine non-adherence. In this article, we present the cases of four patients with schizophrenia undergoing combined treatment with RLAI and clozapine for more than one year after multiple relapses related to clozapine non-adherence. Durations and frequencies of hospitalizations markedly declined after RLAI augmentation. Indeed, three patients receiving RLAI and clozapine for 1.2-3.5 years were never hospitalized during this period. The lengths of hospitalizations before and after augmenting with RLAI were 54.7 +/- 33.1 and 4.2 +/- 4.2 days/year, respectively. Participants also showed great improvements in social skills. These findings suggest the possible beneficial effects of RLAI augmentation in cases of clozapine nonadherence. However, controlled clinical trials are necessary to confirm whether RLAI augmentation represents a useful treatment option for patients who have not adhered to clozapine treatment.