Primary teratomas in the retroperitoneum are very rare in adults. A 32 years old female patient presented with abdominal pain which abdominal computerized tomography revealed right adrenal tumor. The adrenal mass was not originated from adrenal glanol during exploration in the exploration. Frozen section was benign. After surgical removal microscopic diagnosis came as a primary mature cystic teratoma. In case of a retroperitoneal tumor, germ cell tumors should be considered in differential diagnosis and researched before surgery. We describe a case of mature cystic teratoma that was clinically presenting as an adrenal tumor.