Serial changes of neuroradiological findings in a 10-year-old boy with primary germinoma originating in the basal ganglia are reported. He presented with a one year history of slowly progressive right hemiparesis. Although initial computed tomography (CT) scans showed no prominent abnormalities, a slight high-density area in the basal ganglia became conspicuous with cortical atrophy on follow-up scans. Sequential magnetic resonance images showed a homogeneous lesion with clear margin and remarkable postcontrast enhancement. Two cell pattern germinoma was histologically verified by CT guided stereotactic biopsy. Following irradiation, the tumour completely disappeared, however, the atrophy of the cerebral hemisphere and the brain stem progressed, and mild hemiparesis remained. We discuss the neuroradiological features and clinical manifestations of this disease.