Theories of working memory (WM) often distinguish between a central component and peripheral components for verbal and visual information. In the present study, we tested whether musicians differed from non-musicians on WM capacity and structure, with a particular focus on motor memory. We compared individuals with instrumental music training ( n = 91) to those without musical training ( n = 99) on seven WM tasks, measuring visual, verbal, and motor memory. The results showed that the musicians only rarely outperformed non-musicians on WM tasks. As for memory structure, a principal components analysis revealed that the seven tasks loaded onto different components for non-musicians and musicians. In musicians, scores loaded onto three components that represent motor–visual memory, verbal memory, and memory for the movements of others. In contrast, there were only two extracted components for non-musicians. These results suggest that music training leads to greater cross-modal and intermodal integration in WM, as well as specialization within motor memory.