Background: Team-Based Learning is relatively new in medical education. Team-Based Learning was integrated into one medical school's pre-clinical curriculum in 2002.

Purpose: This study compared how medical students' attitudes about the Team-Based Learning process changed between the first and second year of medical school.

Method: 180 students responded to 19 statements regarding their attitudes about Team-Based Learning during their first and second year of medical school. Data were analyzed using a Mann-Whitney U test.

Results: Significant changes in attitudes occurred in the areas of Professional Development, Satisfaction with Team Experience, and Satisfaction with Peer Evaluation but not in the areas of Team Impact on Quality of Learning and Team Impact on Clinical Reasoning Ability.

Conclusion: This study demonstrates that students' attitudes about working within teams, their sense of professional development, and comfort and satisfaction with peer evaluation change in a curriculum using Team-Based Learning.