Myo Nyein Aung,1 Juraiporn Somboonwong,2 Vorapol Jaroonvanichkul,1 Pongsak Wannakrairot3 1Medical Education Unit, 2Quality Management Division and Department of Physiology, 3Academic Affairs Division, Faculty of Medicine, Chulalongkorn University, Bangkok, ThailandBackground: Medical students’ motivation is an important driving factor for academic performance, and therefore medical teachers and educators are often highly interested in this topic. This study evaluated the impact of an academic affair program upon preclinical year medical students’ motivation to study.Design and methods: An intervention study was conducted using a pretest-posttest study design. A total of 296 preclinical year medical students who had just passed their first year and were about to attend their second year at the Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand, participated in the study. The intervention comprised of dialogues for personality development, pictorial expression in groups, as well as small group lectures delivered by senior students giving information on how to prepare for the forthcoming classes. Students’ academic motivation was measured before and after the intervention program, applying the transculturally translated Academic Motivation Scale (AMS). Cronbach’s alpha of Thai version AMS was 0.8992. The average scores in seven scales of AMS were compared between the pre- and posttest results, using the Wilcoxon signed-rank test. The differences were confirmed by using the multivariate analysis of variance.Results: Students’ academic motivation increased after participation in the three-day academic program. There was also a significant increase in introjected extrinsic motivation, which can enhance the students’ self-esteem and feeling of self-worth (P<0.001). Moreover, intrinsic motivation toward accomplishment increased significantly (P<0.001). This is related to the enjoyment of passing academic milestones, and a step ahead of autonomous motivation. Amotivation level declined significantly (P<0.001). The change of academic motivational constructs before and after the intervention was altogether significant (P=0.036, multivariate analysis of variance).Conclusion: After experiencing a three-day intervention, the new students’ motivation advanced along the continuum of self-determination toward autonomous motivation. Therefore, it is considered to be worthwhile conducting an academic intervention to catalyze the evolution of preclinical year medical students’ academic motivation. Moreover, educators and faculties should evaluate the impact of interventions in evidence-based approaches to secure both controlled and autonomous types of motivation.Keywords: medical education, motivation, Academic Motivation Scale, intervention, AMS, medical students