Objective: Training one hand on a motor task results in performance improvements in the other hand, also when stimuli are randomly presented (a process called nonspecific transfer). Corpus callosum (CC) is the main structure involved in interhemispheric information transfer; CC pathology occurs in patients with Multiple Sclerosis (PwMS). Aim of the study was to investigate the CC role in nonspecific transfer of a pure motor reaction-time task in PwMS. Methods: 22 right-handed PwMS and 10 controls were asked to respond to random stimuli with appropriate finger opposition movements with the right (learning) and then the left (transfer) hand. Movements were recorded with a sensored glove to calculate response times. Subregions (ROIs) were selected in the CC on the midsagittal fractional anisotropy (FA) map of each patient, obtained by diffusion tensor magnetic resonance imaging. Mean FA values were calculated in these ROIs to quantify structural damage. We correlated the amount of nonspecific transfer with CC regional FA. Results: PwMS improved motor performance reducing response times with practice with a trend similar to controls and preserved the ability to transfer the acquired motor information from the learning to the transfer hand. A higher variability in the transfer process was found in the PwMS group with respect to the control group, suggesting the presence of subtle impairments in interhemispheric communication in some patients. A significant correlation was found only in the subregion including posterior midbody (r=0.74, p=0.003), that includes fibers connecting primary motor and sensory areas. Conclusion: This finding suggests that posterior midbody is essential for the interhemispheric transfer of information related to pure sensorimotor tasks, and transcallosal interactions between primary motor and sensory areas contribute to motor performance in the transfer hand optimizing the timing of visuomotor processing.