Successful retrieval on a test compared to just re-studying material improves long-term retention—a phenomenon called the ‘testing effect’. This study investigated the role of feedback and collaborative testing on the retention of course material in a tertiary educational setting. Tested material was better retained relative to non-tested material (testing effect), and feedback facilitated correction of errors. Group testing produced higher performance on the initial, but not final test performance, compared to individual testing. This set of findings suggests that to encourage long-term retention, educators should utilise individual formative testing with feedback; theoretical implications are also discussed. Copyright © 2009 John Wiley & Sons, Ltd.