Noncompliance in taking medication is very common among people with schizophrenia, and is a frequent cause of relapse of symptoms. A long-acting injectable formulation that ensures the slow but steady release of risperidone over a period of several weeks would eliminate the need to take medication on a daily basis, and improve compliance. This is an open-label, international, multicenter study in patients with schizophrenia or schizoaffective disorder who either completed study RIS-INT-57 or RIS-INT-61 or who dropped out of RIS-INT-61 after the completion of 3 injection cycles. Patients have to begin this study within 7 days of the final endpoint visit in the RIS-INT-57 or RIS-INT-61 studies. The endpoint visit of RIS-INT-57 and RIS-INT-61 serves as the first visit (Visit 1) of RIS-INT-63, and is considered the baseline of this extension study. Patients who have completed RIS-INT-57 will continue to receive the same dose of long-acting injectable risperidone (25, 50 or 75 mg) as they received during the last 3 months of that study. Patients who have completed or dropped out of RIS-INT-61 will continue to receive the same or equivalent dose of long-acting injectable risperidone as they had received during that study. The blind will not be broken for patients from the RIS-INT-61 study, therefore they will continue to receive double-blind oral medication for the first 3 weeks of this extension study. The total study duration is planned to be at least 1 year. The study hypothesis is that treatment with the long-acting injectable formulation of risperidone every 2 weeks for at least 1 year will be safe and well tolerated, as assessed by adverse event reporting, the extrapyramidal symptom rating scale, laboratory tests, vital signs measurements, physical examinations, body weight measurements, electrocardiograms, and injection site evaluations. Patients will receive injections of risperidone depot in microspheres (25, 50 or 75 mg) in their muscle at 2-weekly intervals for at least 1 year.