OBJECTIVE To present a new case of hydatid cyst of the kidney with a difficult radiographic diagnosis. MATERIAL AND METHODS We describe the clinical, diagnosis and treatment of a complex renal mass and its histological confirmation after surgery. Review of the literature. CONCLUSIONS kidney's hydatidose is an unusual placement of this pathology. It is important to take care in the differential diagnosis in the context of complexes renal masses. There are some diagnosis procedures which can help us to establish it. Surgery is the treatment of choice in the majority of the cases.