The large, hard, non-tender features of neonatal testicular torsion may sometimes lead to the misdiagnosis of a testicular tumor. The authors present the case of a 1-week old male neonate in whom the differential diagnosis between testicular torsion and a tumor proved difficult. Based on serial physical examinations and serial color Doppler ultrasonography findings, the initial diagnosis was a testicular tumor with/without torsion and a concomitant communicating hydrocele. However, the intraoperative findings did not support the existence of testicular torsion. A left radical orchiectomy and contralateral orchiopexy with herniorrhaphy were undertaken, but somewhat surprisingly, the final pathologic findings demonstrated a left testicular torsion.