Background. To evaluate the effectiveness of a new ultrasonographic method for discrimination of successful and failed anti-incontinence operations. Methods. Ninety-six patients who had undergone anti-incontinence operations for the diagnosis of pure genuine stress incontinence due to bladder neck hypermobility were evaluated by perineal ultrasonography and 1 hr standardized pad test 6, 12 and 24months after their operations. The distances from the bladder neck to the lower tip (A) and to the posterior midpoint of symphysis pubis (B) were measured at rest and during stress. Bladder neck mobility (Mu) was obtained by two-caliper method. After superimposing the symphysis pubis of the frozen images, the bladder neck positions at rest and during stress were plotted on an x-y coordinate system by using computer programs and the corresponding x and y-values (X and Y) calculated and the second bladder neck mobility (Mc) were measured on the x-y coordinate system by computer. Unpaired and paired-t-tests were used for statistical analysis. Results. Ten (10.4%) patients had recurrent urinary incontinence, while 86 (89.6%) were continent 24months after the operation. The incontinent patients had significantly longer Mu, Mc and distance B during stress and lower X and Y-values during stress than the continent patients at the last control (P < 0.001). When the previous results were compared, the incontinent patients had significantly lower Y-values during stress and greater Mc values beginning 6 months after the operation, while they were still continent (P < 0.01). Once present, the significant differences between the incontinent versus continent patients persisted from that point onward. Conclusions. Measurement of the bladder neck mobility on an x-y co-ordinate system could discriminate the failed and successful operations and predict the outcome of the surgery.