Brain size is a useful parameter describing ontogenic character and function. Despite its potential contribution to functional study and diagnosis of disease, it has been hampered by poor assessment tools in vivo and postmortem changes. Recent development of medical imaging techniques such as MRI and CT enable us to understand brain structures in vivo. Many morphometirc studies of the brain has given us new insights in the field of functional neuroanatomy and neuropsychiatric diseases. In spite of these advances, volumetric data of normal Korean brain is not available yet. As an initial approach to Korean standard brain size, we measured the cerebellar volume between 20 and 80 years old Koreans. The MRI films free from lesions in brain was analyzed and measured by NIH image program. The Korean cerebellar volume were ranged between 86.2cm(3) and 141.3 cm(3) and average male cerebellum volume was significantly larger than that of female[male : 118.2+/-11.2cm(3)] > female : 108.0+/-9.6cm(3), P=0.1021E-07<0.05]. And we could not find volume change according to aging process. This is the first report on normal Korean cerebellar volume and the presence of gender difference in the Korean cerebellar volume. These data will be used for the standard useful in studying cerebellar function and cerebellum associated disorders in the future.