RESUMEN
PURPOSE: The aim of this study is to analyze the interaction system between instructor and learners and strive for class improvement based on the evaluation. METHODS: Flanders Interaction Analysis System classifies instructor and learner's speaking into ten items. Observer analyzed every verbal interaction in class and filled out classified table recording the number of adequate category every three seconds. RESULTS: In this study, observed class spent 94.3% of time on teaching and learning activities. So it could be said that the class used time effectively without any waste. The instructor showed indirect teaching method and as a result, the students showed more initiative statements than simply answering questions. The major pattern was question--> answering questions, and incidental pattern was lecture--> initiative statement--> silence or disorder--> initiative statement--> lecture. CONCLUSION: In medical education, small group lesson is one of the popular teaching methods where Flanders interaction can be analyzed effectively. Using such evaluation, we can promote better teaching and learning.