This case study investigated 12 graduate students' online collaborative experiences and attitudes in an instructional design course. The instructor divided students into 4 groups based on their academic backgrounds. Content analysis of asynchronous group discussion board messages was used to measure degrees of collaboration of each group in terms of participation, interdependence, synthesis, and independence. In addition to the group discussion board messages, 3 other data sources--group projects, student attitude survey, and student reflections--were analyzed. Results showed that ineffective communication, conflict among group members, and negative attitude toward group work posed major challenges to online collaboration. The results also showed that the more collaborative groups produced better quality projects and had more positive attitudes toward online collaborative learning. However, the social loafing phenomenon was present in each group. Recommendations on how to successfully implement group collaboration in online courses are provided. (Contains 3 tables.)