Flipped teaching (FT) has caught educators' attention due to its success in engaging students through pre- and in-class activities. To learn if FT improved student performance, scores from the quizzes and exams of a fully flipped classroom with retrieval exercises were compared with those of five semesters of traditional lecture-based [unflipped (UF)] teaching in an undergraduate sophomore-level physiology course. Student attitude surveys were also evaluated. Student performance on both the quizzes and exams was significantly higher in the FT class in general compared with that of the UF teaching. Interestingly, however, when the individual exam scores were compared between the two styles, the scores for students in the FT were significantly higher for exams 2 and 3, yet lower for exam 1. The shift in performance from exam 1 to exams 2 and 3 is likely explained by the need for time to adjust to the new teaching style. Students reported an overall positive perception of FT in their course evaluations at the end of the semester. In conclusion, FT improved student performance compared with that of lecture-based traditional teaching practice, but required some time to adjust in the beginning of the semester.