LEARNING a motor skill sets in motion neural processes that continue to evolve after practice has ended, a phenomenon known as consolidation(1-4). Here we present psychophysical evidence for this, and show that consolidation of a motor skill was disrupted when a second motor task was learned immediately after the first. There was no disruption if four hours elapsed between learning the two motor skills, with consolidation occuring gradually over this period. Previous studies in humans and other primates have found this time-dependent disruption of consolidation only in explicit memory tasks(5-12), which rely on brain structures in the medial temporal lobe(9,13,14). Our results indicate that motor memories, which do not depend on the medial temporal lobe(8,15), can be transformed by a similar process of consolidation. By extending the phenomenon of consolidation to motor memory, our results indicate that distinct neural systems share similar characteristics when encoding and storing new information.