Retroperitonal teratomas are rare. We report on a case of a retroperitoneal secondary localisation of a gonadal teratoma in a patient who had developed primary testicular teratoma 12 years previously. The retroperitoneal mass was detected with an abdominal CT requested for the management of a non-specific abdominal pain. CT and MRI examinations showed cystic retroperitoneal masses combined with calcifications and peripheral enhancement. Review of the literature is presented, including the common differential diagnoses to be considered.