Successive relearning (SR) combines retrieval practice across spaced study sessions. In particular, students attempt to recall to-be-learned information (with feedback) during each session until all concepts are correctly recalled and then return to the same material to repeat retrieval practice on multiple spaced practice sessions. Thus, students must begin using this technique several weeks before an exam, which may decrease their motivation for using it. The main question for the present research is: Will providing students with a small amount of class credit increase their likelihood of engaging in SR? First-year medical students in a Principles of Medical Research course were provided with an SR program that included (a) virtual flashcards containing definitions of statistical concepts (e.g., levels of measurement, central tendency, odds ratios, etc) that students practiced retrieving, (b) feedback after each retrieval attempt, and (c) schedules for using each virtual flashcard stack across three spaced practice sessions. Students received incentives in terms of class credit to complete SR sessions for half of the content but no incentive for the other half. A delayed practice test was administered to evaluate the impact of SR on retention. Using SR (vs. not using it) did boost retention of the concepts. And, most important, credit had a major impact, with students completing over 90 percent of the SR sessions that were assigned to receive credit but under 10 percent of the SR sessions that were optional.