20 subjects with Morgagni-Turner's syndrome have been extensively investigated for structural or functional abnormalities of the urinary tract. This investigation was planned owing to the observation by Morgagni, who described the first case of gonadal agenesis associated with a congenital anomaly of the kidneys, and in consideration of the embryological connection between the gonadal and the excretory « Anlagen ». Moreover, to this respect, previous investigations have been very indicative. The patients were subjected to conventional X-ray examination of the urinary tract and to radionephrography with 131 I-hyppuran and, when necessary, to renal scintigraphy with 197 Hg-neohydrin. In a group of patients inulin and PAH clearances were also determined. More than half of the patients had important abnormalities: horseshoe kidneys (5 cases), pyeloureteral duplicity (3 cases), unilateral renal aplasia (2 cases), rotation of the kidneys (1 case); seven further cases showed pyelic dilatation and hypotonia associated with frankly abnormal 131 I-hyppuran nephrograms. 3 out of 4 cases, in which clearance studies were performed, showed marked reduction of glomerular filtration rate and renal plasma flow, even though conventional urography showed no pathological change. It is evident that the urinary tract is very often abnormal in this syndrome; the abnormalities are usually structural, rarely purely functional. Thus, it seems even more justified to indicate the syndrome with both the names of Morgagni and Turner.