Abdominoscrotal hydrocele is extremely rare in children. A case is presented of an unusually large abdominoscrotal hydrocele in a child, with secondary right hydroureteronephrosis due to contiguous pressure and right cryptorchidism. This entity, although unusual, should be considered in the differential diagnosis of a lower abdominal mass in children, as well as a cause of hydroureteronephrosis. Diagnosis is made with ultrasound, computerized tomography and occasionally excretory urography. Complete surgical excision through a groin incision is recommended, but optional inguinoabdominal or abdominal incisions have been reported. After surgical removal, healing is usually complete, including regression of the hydroureteronephrosis.