Objective: Continuous treatment is an important goal in the management of schizophrenia. Retention rate is a well-recognized global measure of effectiveness that integrates patients' and clinicians' judgment of efficacy, safety and tolerability. Furthermore, all-cause discontinuation was used as a primary outcome measure in a large effectiveness study (Clinical Antipsychotic trial of Intervention Effectiveness or CATIE). The current study utilized longitudinal claims data from Ontario Drug Benefit (ODB) recipients in Ontario, Canada to compare retention rates for typical and atypical antipsychotic medications with different formulations. Methods: Longitudinal data were obtained for ODB recipients that were initiated on antipsychotic therapy in July 2006. ODB recipients were followed from their first claim for the specific target drug to their last claim in a 12-month period. Rates of retention were determined throughout and up until 12 months. Descriptive analyses were performed. Retention rates were reported for depot (long-acting injectable) risperidone; oral atypical antipsychotics including olanzapine, risperidone, and quetiapine; orally disintegrating tablet formulations of risperidone and olanzapine; oral typical antipsychotics (pooled); and depot typical antipsychotics (pooled). Results: From July 2006 – June 2007, 12-month retention rates were lowest with oral typical (29% of recipients), depot typical antipsychotics (30%), and risperidone orally disintegrating formulations (30%). Retention rates for oral atypical antipsychotics were 41% for olanzapine, 46% for risperidone and 50% for quetiapine. Retention on risperidone long-acting injectable were the highest with 73% of recipients retained over 12-months. Conclusion: Retention rates were lowest with typical antipsychotics and risperidone orally disintegrating tablets and highest with depot risperidone formulation. This finding is consistent with the results reported in the CATIE study where only 25-45% of patients continued on oral treatment after one year. Retention on medication is an important aspect of patient outcomes in schizophrenia; these data suggest that retention on depot risperidone may be improved compared to other treatments.