We set out to determine if insertion of a retropubic tension-free vaginal tape (TVT) sling at the time of pelvic organ prolapse surgery improves continence outcomes in women with pre-operative occult stress incontinence (OSI) or asymptomatic urodynamic stress incontinence (USI). We conducted a randomised controlled study of prolapse surgery with or without a TVT midurethral sling. The preand post-operative assessment at 6 months included history, physical examination and urodynamic testing. Quality of life (QOL) and treatment success was assessed with the UDI-6 SF, IIQ-7 SF and a numerical success score. The primary outcome was symptomatic stress urinary incontinence (SUI) requiring continence surgery (TVT) at 6 months. Long-term follow-up continued to a minimum of 24 months. Secondary outcomes were quality of life parameters. Eighty women received prolapse surgery alone (n=43) or prolapse surgery with concurrent TVT (n=37). Six months following prolapse surgery 3 out of 43 (7 ) patients in the no TVT group requested sling surgery compared with 0 out of 37 (0 ) in the TVT group (ARR 7 [95 CI: 3 to 19 , p=0.11). After 24 months there was one further participant in the no TVT group who received a TVT for treatment of SUI compared with none in the TVT group (4 out of 43, 9.3 versus 0 out of 37; ARR 9.3 [95 CI: -1 to 22 , p=0.06). Both groups showed improvement in QOL difference scores for within-group analysis, without difference between groups. These results support a policy that routine insertion of a sling in women with OSI at the time of prolapse repair is questionable and should be subject to shared decision-making between clinician and patient.