At the Mayo Clinic from January 1960 through December 1975, 673 patients underwent a modification of the Marshall- Marchetti-Krantz operation as a primary or secondary procedure for recurrent stress incontinence. There were 96 patients (14%) lost to follow-up, and 28 patients have died; 549 patients have been followed for 2-16 years. Of the 549 patients, 227 underwent the procedure as a primary operative effort; 91% of these were cured or much improved from socially disabling stress urinary incontinence, 7% were unchanged, and 2% became worse. There were 322 patients who underwent surgery for persistent or recurrent stress incontinence. This group had had a total of 740 previous unsuccessful operations (an average of 2.3 per patient) specifically for stress incontinence; 90% of these patients were cured or much improved, 5.3% were unchanged, and 4.7% became worse. The Marshall-Marchetti- Krantz operation is an effective and safe procedure associated with minimal morbidity and no mortality.