We report a case of familial testicular cancer associated with undescended testes in two brothers. The older brother (49 years) presented with a testicular tumor located in the right inguinal canal. The pathologic diagnosis was pure seminoma. Computerized tomography revealed iliac and retroperitoneal lymph node metastases. Four years later, the younger brother (44 years) developed bilateral testicular tumors, one located in the inguinal canal, the other located in the pelvic cavity. The pathologic diagnosis of both tumors was pure seminoma. Radiological examination revealed retroperitoneal lymph node metastases. Both patients received cisplatin-based combination chemotherapy as the initial treatment. The older brother suffered from repeated recurrences with lymph node metastases in the iliac and inguinal regions, but he was successfully treated with high-dose chemotherapy. The younger brother achieved long-term remission after retroperitoneal lymph node dissection following initial chemotherapy. We briefly review the reported cases of familial testicular cancer and discuss the association of the maldescent of the testes and familial testicular cancer cases.