Using a long-acting antipsychotic to improve adherence early in the illness may reduce relapse rates and promote sustained remission, thereby improving the long-term outcome of schizophrenia. We assessed whether risperidone long-acting injection (RLAI) could be used safely and effectively in the treatment of recent-onset psychosis. Fifty patients aged 15 to 43 years with newly diagnosed schizophreniform disorder or schizophrenia were treated with RLAI 25 to 50 mg every 2 weeks for 2 years. Thirty-six patients (72%) completed the trial. Of 39 (78%) who showed a clinical response of 50%, 4 relapsed. Thirty-two patients (64%) achieved remission. Mean maximum increase in Extrapyramidal Symptoms Rating Scale total score was 1.4 (95% confidence interval, 0.61-2.10; n = 50); 10 patients required anticholinergic medication, and 1 subject developed persistent dyskinesia. Prolactin levels were elevated in 18 patients, 4 of whom reported possible prolactin-related adverse events. Mean increase in body mass index to last visit for all patients was 4.8 kg/m (SD, 3.8 kg/m). The final RLAI dose was 25 mg for 54% of patients, 37.5 mg for 30%, and 50 mg for 16%. This preliminary study suggests that RLAI was overall well tolerated and appears to be effective in recent-onset psychosis. Further investigation is warranted.