THE following case is reported because of the rarity of the condition and because it illustrates certain principles of management. The previously reported cases in the English literature are reviewed.Case Report.-A white male aged 17 years was involved in a road traffic accident and admitted to another hospital. He had sustained a blow to the left loin. There was no evidence of bony or major soft tissue injury, but an intravenous pyelogram demonstrated that an incomplete rupture of the left upper ureter had occurred with extravasation of urine (Fig. 1). He was treated conservatively with antibiotic cover until his symptoms of local tenderness subsided. No operative intervention was carried out. FIG. 1 Intravenous pyelogram shortly after injury, showing partial rupture of the proximal portion of the left ureter with extravasation of contrast medium.He came under our care approximately 6 weeks after his injury, at which time he had no complaints and felt well. Physical examination revealed no abnormalities. His urine was sterile and contained no abnormalities and his blood count, blood urea and electrolytes were all within normal limits. Intravenous pyelography showed the left kidney to be enlarged with some diminution of function. There was a hydronephrosis present secondary to a partial obstruction of the left ureter just distal to the pelvi-ureteric junction. There was a 1.5 cm. narrowed segment at this site (Fig. 2). The appearances were those of partial obstruction of the left kidney by a fibrotic stricture of the proximal ureter.