We investigated the objective coexisting rate of stress urinary incontinence and pelvic organ prolapse, and also compared the treatment outcomes in patients who had both conditions, treated by a corrective operation on the basis of a precise preoperative evaluation. We reviewed 97 cases who underwent urodynamic studies and evaluation of the prolapse according to the Pelvic Organ Prolapse Quantification (POP-Q) system from among patients who were admitted for treatment of either stress urinary incontinence or pelvic organ prolapse. A Burch urethropexy, either alone or with a parvaginal repair, was done to correct the stress urinary incontinence, as well as additional operations to correct prolapse of stage II or more. The patients were evaluated postoperatively for the stress urinary incontinence and the degree of prolapse at every visit. Nineteen of 30 (63.3%) patients who were admitted with stress urinary incontinence had a coexisting pelvic organ prolapse, most often of the anterior wall. In 42 of 67 (62.7%) cases admitted with pelvic organ prolapse there was a coexisting stress urinary incontinence. A total of 61 patients who had both conditions were followed for 12 months postoperatively. The recurrence rate of stress urinary incontinence and prolapse (all of which were stage II) was 3.3% and 18.0%, respectively. It was noted that the greater the preoperative stage, the higher the recurrence rate (stage II 4.35%; stage III 25.0%; stage IV 33.6%). The coexisting rates of pelvic organ prolapse in patients having stress urinary incontinence, and stress urinary incontinence in patients having a pelvic organ prolapse, were both high. Therefore, when a preoperative evaluation that simultaneously considers both conditions and the correcting surgery is based on this evaluation, the recurrence rates of both conditions could be lowered.