The effects of age and gender on cerebellar size have not been established yet. To understand these effects, the area of cerebellar vermis and the volume of cerebellum were measured using serial magnetic resonance images of 124 Korean adults free of neurologic symptoms and signs. Cerebellar volume of male was significantly larger than that of female, although the size of vermis did not show significant gender difference. Correlation analysis revealed that cerebellar volume was not affected by aging. Regressional analysis demonstrated that female vermis had a tendency to shrink after age of 50, whereas male vermis and total cerebellar volume in both sexes were not altered with aging. The different response of vermis with aging and maintenance of cerebellum volume need to be more explored.