Retroperitoneal teratoma represents 1-11% of primary retroperitoneal tumors [1]. It is generally benign whether mature or immature. The treatment is surgical and the prognosis is excellent in the absence of complications. We report a case of mature retroperitoneal teratoma in an 8-year-old girl revealed by an isolated right paramedian abdominal mass. CT revealed a right suprarenal mass, fatty density with calcifications, without invasion of neighboring structures, measuring 124 mm in transverse diameter, 104 mm in anteroposterior diameter and 174 mm in height. Management consisted of complete excision of the tumor without incident.