We prospectively assessed sexual function before and after a tension-free vaginal mesh ( TVM) procedure for pelvic organ prolapse ( POP) . From April 2007 to March 2009, a total of 42 patients, who reported having an active sex life preoperatively underwent TVM for POP. Female sexual function was evaluated with the self-reporting, multiple-domain Female Sexual Function Index (FSFI) . We administered the FSFI to all of the patients before and at 3, 6, and 12 months after surgery. The mean age at surgery was 61.3±7.1 years. Before the TVM surgery, the FSFI score was very low ( 12.5±9.0) . The total FSFI score was improved significantly at 12 months after surgery ( 17.4±7.7) . The Arousal, Lubrication and Orgasm domains were significantly improved at 12 months after surgery. POP appears to have a significant negative impact on female sexual function. Our findings indicate that TVM for POP improved sexual function in a group of Japanese women with POP.