Cortical cerebellar degeneration was found in a 28-year-old man with testicular neoplasm. The patient, who had undergone a left orchidectomy for the testicular tumor, developed progressive cerebellar symptoms with mental changes 7 months later. The autopsy revealed the spread of a malignant germ cell tumor of the testis, and cortical cerebellar degeneration in the central nervous system (CNS) which was characterized by almost complete loss of Purkinje cells and degeneration of the both dentate nuclei and superior cerebellar peduncles. The present case is the first of cortical cerebellar degeneration combined with testicular neoplasms.