One hundred female patients with stress incontinence have been operated on by means of modified stamey's endoscopic bladder neck suspension procedure, i.e. quantifying the thread tension for bladder neck suspension. Twelve patients had 1,000 grams in the nylon loop, 5,800 grams, 9,700 grams, 25,600 grams and 49,400 grams. A follow-up period varied from 10 to 32 months (mean: 20.5 months). A 60-min pad-weighing test revealed urinary loss of 1.0 to 196.0 grams/hour (mean: 36.0) prior to operation. 1. The modified Stamey's procedure was successful in 95 patients (95%). The appropriate thread tension for bladder neck suspension was 400 grams. 2. Various complications were encountered: removal of unilateral nylon suture was necessitated in 2 patients, bleeding from operative wound in 2, bladder tamponade in 2, and clean intermittent catheterization for more than one month in 4. 3. Micturition parameters, i.e. maximum and average flow rates, temporarily got worse post-operatively. Maximum urethral closure pressure decreased and functional profile length elongated which were significantly different from those of pre-operative values. 4. Questionnaire sent to the patients revealed that 89 percent of them were satisfied with the operative results but 11 percent were not. 5. The modified Stamey's procedure is simple to perform and prevents over-tightness of nylon loops. We conclude that this operative method is the treatment of choice for correction of stress incontinence.