Effective interprofessional collaboration is an important factor in addressing health care needs and priorities. Educators and health care practitioners have argued that interprofessional education (IPE) is necessary to equip students with the knowledge, skills, attitudes, and behaviors to work collaboratively and ultimately deliver enhanced patient/client care. The University of Toronto has implemented an introductory IPE session for approximately 1000 health science students that focuses on teamwork. This session provides students with an opportunity to be sensitized to the client's perspective and become familiar with roles and perspectives of different professions. A mixed method pre/post research design was developed to examine changes in students' perceptions and attitudes regarding IPE following their participation in this session. This study also endeavored to explore the pedagogic effectiveness of this large-scale IPE session. Students completed pre and post surveys based on the Interprofessional Attitudes Questionnaire and the Interdisciplinary Education Perception Scale. A total of 399 surveys were matched for pre/post analysis, and 25 students participated in follow-up focus group interviews. Findings from this study reveal that a significant shift in many indicators occurred after this single intervention. Despite the large numbers of students, which meant a complex range of logistical factors to negotiate, our findings indicated that it is feasible to deliver a successful IPE session to a large cohort of first-year students. We suggest that the findings presented in this report can be of value to other interprofessional groups of course developers.