Multimedia instructional materials are indispensable in the holistic process of instructional design, particularly for asynchronous online courses. The purpose of the current study was to investigate the impacts of background classical music played in an instructional video on learners' retention. The video started with a pretraining message followed by a narrated instructional content. The results of the study suggest that although classical background music in the pretraining message significantly improved learners' retention, it did not have a remarkable influence when embedded in the narrated content. Practical implications and suggestions for further research are provided.