This paper analyzes the renal and ureteral complications caused by urethral stenosis. A total of 180 patients with stenosis, 175 males and 5 females, were reviewed. There were 55 renal-ureteral complications in 37 patients (20.55%). In order of frequency, complications were as follows: renal failure (36%), ureterohydronephrosis (33%), chronic pyelonephritis (16%), vesico-ureteral reflux (11%), and post-obstructive renal annulment (4%). Most complications were reversible. However, renal function impairment was irreversible in 3 cases due to I.R.C., as well as in 2 cases due to post-obstructive renal atrophy-annulment. Nine patients showed chronic pyelonephritis morphological changes. Urinary infection occurred in 28 patients (76%), and in 50% of them was due to ureolytic germs. The best procedure to treat these complications is based on a correct prevention, eradicating the associated urinary infection and correcting the causative obstructive problem. Nonetheless, surgery was required in 5 patients (13.50%) and extracorporeal lithotripsy for the lithiasis associated to stenosis in other 5 patients (13.50%). We conclude that although those complications have a high incidence, their ultrasound diagnosis is easy and the prognosis reversible once the stenosis is corrected. Risk factors for development are: male sex, the sixth decade of life and a long evolution stenosis associated to urinary infection. Finally, a review of the scarce literature on this frequent but forgotten chapter of obstructive uropathy is made.