BackgroundVirtual patient (VP) cases are an effective teaching method, although little is known about how to design and implement them for maximum effectiveness. The aim of this study was to explore the effect of case design and teamwork on students’ learning outcome.MethodsOne hundred forty-six undergraduate medical students participated in a mandatory medical computer science course consisting of five seminars. At the end of each seminar, they worked on one VP case, either in teams of two or individually. Each student filled out an introductory and a final survey and a feedback sheet after completing each case. Additionally, there was a surprise multiple choice (MC) test after the last seminar with three questions regarding each case.ResultsStudents with more clinical experience and students who had worked in a team performed significantly better on MC questions. Students with less clinical experience more frequently used information which had been positioned less prominently on the case material. Certain aspects of case design were rated more positively by students who had an interest in e-learning. In general, students preferred to work on cases for less than 15 minutes.ConclusionsClinically more advanced students and students working with a partner seem to benefit most from short VP cases with prominently presented information.