BACKGROUND. In training faculty as tutors for problem-based learning (PBL), certain aspects (domains) of teaching methodology are highlighted in the medical education literature. These are content, cognitive processing, and group dynamics. The authors contend that the amounts of attention given to these domains in faculty and student development have not been equal and that group dynamics needs further attention. METHOD. In March 1993 the authors conducted a time-lapse study that involved 27 first-year students and three faculty in three PBL groups at the University of Toronto Faculty of Medicine. The purpose of the study was to determine faculty and student perceptions and knowledge of effective group dynamics, and to develop recommendations for student and faculty training. A qualitative approach was used that combined projective questions, post-tutorial questionnaires, and live and videotaped observations. RESULTS. Observations and analysis of the data revealed a generally low awareness of effective group dynamics and the absence of a mechanism for reflection that could help groups analyze and learn from their behaviors. The results also revealed a discrepancy between self-reported behavior and observed behavior. For example, the students and faculty perceived their groups as generally “working well as a team,” but observers noted that several aspects of group productivity (such as the articulation of goals and planning for future sessions) were not addressed. CONCLUSION. The authors recommend that medical schools develop comprehensive training programs to teach group members to evaluate group performance and engage in open discussion of effective and ineffective behaviors.