This study investigated whether using multimedia-based instructional material in a problem-based social studies simulation enhances student learning about world issues, increases interest in social studies, and generates positive attitudes toward the instruction. The GlobalEd Project, a Web-based international negotiation simulation embedded in the middle school social studies curriculum, was used in this investigation. The study employed a quasi-experimental design with a multimedia group (MG) and a text group (TG). A total of 190 students participated in the study. Results indicated that students in the MG had marginally larger gains in knowledge and interest than their counterparts in the TG. In addition, students in the MG used the Web site more extensively than students in the TG. Directions for future research and multimedia developers are discussed. (Contains 6 tables and 1 figure.)