Benefits of collaborative testing have been identified in many disciplines. This study sought to determine whether collaborative practical tests encouraged active learning of anatomy. A gross anatomy course included a collaborative component in four practical tests. Two hundred and seven students initially completed the test as individuals and then worked as a team to complete the same test again immediately afterwards. The relationship between mean individual, team, and difference (between team and individual) test scores to overall performance on the final examination (representing overall learning in the course) was examined using regression analysis. The overall mark in the course increased by 9% with a decreased failure rate. There was a strong relationship between individual score and final examination mark (P < 0.001) but no relationship for team score (P = 0.095). A longitudinal analysis showed that the test difference scores increased after Test 1 which may be indicative of social loafing and this was confirmed by a significant negative relationship between difference score on Test 4 (indicating a weaker student) and final examination mark (P < 0.001). It appeared that for this cohort, there was little peer-to-peer learning occurring during the collaborative testing and that weaker students gained the benefit from team marks without significant active learning taking place. This negative outcome may be due to insufficient encouragement of the active learning strategies that were expected to occur during the collaborative testing process. An improved understanding of the efficacy of collaborative assessment could be achieved through the inclusion of questionnaire based data to allow a better interpretation of learning outcomes.