The cerebellum is involved in the learning and retention of motor skills. Using animal and human models, a number of studies have shown that long-term motor skill training induces structural and functional plasticity in the cerebellum. The aim of this study was to investigate whether macroscopic alteration in the volume of cerebellum occurs in basketball players who had learned complex motor skills and practiced them intensively for a long time. Three-dimensional magnetic resonance imaging volumetry was performed in basketball players (n = 19) and healthy controls (n = 20), and the volumes of cerebellum and vermian lobules were compared between two groups. Although there was no macroscopic plasticity detected in the cerebellum as a whole, detailed parcellation of cerebellum revealed morphological enlargement in the vermian lobules VI-VII (declive, folium, and tuber) of basketball players (P < 0.0166), which might then be interpreted as evidence for plasticity. This finding suggests that the extensive practice and performance of sports-related motor skills activate structural plasticity of vermian lobules in human cerebellum and suggests that vermian VI-VII plays an important role in motor learning.