Online quizzes were introduced into an undergraduate Exercise Physiology course to encourage students to read ahead and think critically about the course material before coming to class. The purpose of the study was to determine if the use of the online quizzes was associated with improvements in summative exam scores and if the online quizzes were valid predictors of summative exam performance. A retrospective analysis was performed on the course scores from three different groups of Exercise Physiology students. Students in "group 1" completed the original version of the course, those in "group 2" completed an updated version of the course that included more rigorous exam questions, and those in "group 3" completed the same updated version of the course but with the addition of 10 required online quizzes. Results showed that the overall mean summative exam score from "group 3" was significantly higher than that from "group 2" (81.79 [plus or minus] 8.26 and 78.72 [plus or minus] 9.61, respectively). A significant positive correlation (r = 0.50) was also found between individual mean online quiz scores and individual mean exam scores for those students in "group 3". It was concluded that the formative online quizzes did enhance summative exam performance and that the online quizzes were valid predictors of exam performance. (Contains 5 tables and 2 figures.)