Interactive Simulated Patient (ISP) is a computer-based simulation tool designed to provide medical students with the opportunity to practice their clinical problem solving skills. The ISP system allows students to perform most clinical decision-making procedures in a simulated environment, including history taking in natural language, many hundreds of laboratory tests (e.g., images and endoscopy), and physical examination procedures. The system has been evaluated in a number of courses at three universities, Karolinska Institutet and Uppsala University in Sweden, and Stanford University in the United States. This article describes a study conducted in 2002, with an emphasis on results that pertain to collaboration between students. Results indicate that ISP is engaging and stimulates more active student involvement than traditional paper-based case presentation methods and that students seem to collaborate more easily when using ISP compared to traditional paper-based methods.