Although many schizophrenia patients currently take oral antipsychotic medications, it is estimated that up to 75% of them have difficulty adhering to the daily oral regimen. Long-acting injectable formulations may eliminate the need for daily medication and enhance patient compliance with the treatment regimen. This safety study is an extension of a randomized, double-blind, multicenter, parallel group study that investigates effectiveness and safety of risperidone injected intramuscularly in patients with schizophrenia or schizoaffective disorder. The present open-label study evaluates 3 different doses of a formulation of risperidone injected into the muscle at 2 week intervals for at least 1 year in patients with these conditions. Assessments of effectiveness include the Clinical Global Impression (CGI) overall severity of illness scale. Quality of life will be assessed by the SF-36 Health Survey. Safety evaluations include incidence of adverse events, physical examinations, and evaluations of the injection site, clinical laboratory tests, electrocardiograms (ECGs), and Extrapyramidal Symptom Rating Scale (ESRS), a scale assessing muscle tone, gain, and abnormal movements. Injections every 2 weeks for at least 1 year, beginning at 25milligrams[mg] and increasing to 50mg or 75mg (maximum dose). Dosages may be increased or decreased at investigator's discretion. During the first 3 weeks, risperidone tablets (2mg) once daily to supplement injectable risperidone.