We considered 49 patients suffering from urinary stress incontinence, operated from January 1984 to December 1989 by Marshall-Marchetti modified after Symmonds procedure. 13 patients had one or more previous surgical procedures. We made urodynamic preoperative tests and a stress test (after Ferrari) in all our cases. We obtained: complete recovery in 80% of our cases, improvement in 14% and failure in 6%; particularly the recovery percentage in our patients operated for the first time was the 97.2%; in the recurrences we had complete success in 46%, an improvement in 38.5% and surgical failure in 15.5%. Complications were observed in 1 patient affected by pubic osteitis, treated with medical therapy. Only 3 patients had an incomplete bladder emptying one year after the surgical operation, with value of the post micturitional residual volume of about 1/3 of the maximal cystometric capacity.