Lesions of the retrorectal space have a wide variety that are inflammatory, neoplastic, and congenital in origin can be encountered. Dermoid cysts are of developmental origin and are included in the differential diagnosis of retrorectal lesions. Accurate diagnosis, localization, and characterization of retrorectal lesions will affect surgical management. We describe TPUS, CT and MRI findings of a retrorectal dermoid cyst in a female adult patient. Especially TPUS is a value diagnostic method that can be used in the follow up of patients which is not operated