The authors report 18 cases of a vascular pathology of the kidney or of its excretory system presenting with heavy and recurrent haematuria. In contrast to data in the literature, their series includes a majority of capillary angiomas (8 cases), as against 6 aneurysms, 2 arteriovenous fistulae and 2 peripyelo-ureteric varices. Of the six arterial aneurysms, all recognised by arteriography, 4 underwent surgery: 2 endo-aneurysmorrhaphies with success, 1 nephrectomy for rupture of the aneurysm and 1 nephrectomy made necessary by the multiplicity of aneurysms inaccessible in situ. Both cases of arteriovenous fistula were recognised by arteriography. One was treated by polar nephrectomy (success) whilst the other underwent nephrectomy after failure of an attempt at embolisation. Of the two cases of peri-uretero-pelvic varices identified by selective phlebography under cover of an intra-renal-artery injection of angiotensin, only one was treated successfully by excision of the varicosities. The eight cases of capillary angioma were divided into two groups: one, of 4 cases where the diagnosis was made by selective renal phlebography without angiotensin and renal arteriography; and another of 4 cases not identified by these vascular investigations. In these 4 cases, after elimination of Berger's disease by a surgical renal biopsy, the authors exposed the kidney, performed a pyelocalyscopy during a period of haematuria, localised the haemorrhagic segment of the kidney and treated the lesion by partial nephrectomy in the presence of a pathologist to immediately identify the haemorrhagic lesion and examine it histologically. Amongst the 7 angiomas treated, 5 partial nephrectomies gave successful results whilst two nephrectomies were necessary: one because of a diagnostic error and the other following failure of an attempt at hyperselective arterial embolisation.