32 patients with stress urinary incontinence were investigated by bead chain urethrocystography (UCG) and simultaneous urethrocystometry (UGM) before and after operation. 12 patients were incontinent postoperatively. Two important determinants of the operative success emerged. Firstly, an operation-induced decrease in the urethral inclination angle or urethral mobility of at least 40 % was associated with a success rate of 81 %, while in cases with a smaller reduction the success rate was only 27 %. Secondly, excessive urethral relaxation at stress, as determined by UCM, was a sign of a poor prognosis for the operative treatment of incontinence. If the index of urethral relaxation at stress remained smaller than 0.60, none of the operations were successful despite the correction of the urethrovesical anatomy. In these cases the poor intrinsic urethral properties or general laxity of the pelvic floor may have interfered with the operative results. A positive correlation existed between urethral mobility and urethral relaxation at stress. A combination of UCG with urodynamic methods seems to give additional information on the factors contributing to postoperative incontinence.