Background: Research emphasizes the need for instructional methods and tools which can improve BLS performance or reduce instructional time. Aim: To evaluate the efficiency of four 20 min reciprocal learning settings with task cards for acquiring BLS. Methods and materials: 72 university students were paired and randomized into four groups to learn BLS in 20 min with task cards. Groups differed in the implementation of two instructional variables, namely role switching and role definition. BLS performance was measured before (baseline), immediately after (intervention) and 2 weeks later (retention). Results: At intervention and retention, all groups achieved between 71 and 81% of the maximum total BLS score. At retention significantly more students from the group where role switching and role definition were implemented performed the complete BLS sequence. Conclusion: This study demonstrated that implementing role switching and role definition in a reciprocal learning setting with task cards fosters BLS skill retention.