ABSTRACT Introduction Overactive bladder (OAB) is a common condition, especially in middle aged women, requiring long term therapy with anticholinergics to maintain symptoms relief. The aim of the study was to determine the effect of tolterodine extended release (ER) used for OAB treatment on the sexual function of women. Materials and Methods Between August 2010 and August 2014, 220 women with confirmed OAB, attended Urogynecology Outpatient Clinic and were prospectively enrolled in this study. 158 women were evaluated, with a comprehensive history, physical examination, urodynamic studies and Female Sexual Function Index (FSFI) questionnaire. 73 patients of group A (control group) received no treatment and 85 patients of group B received an anticholinergic regimen - tolterodine ER 4mg once daily. Data were evaluated again in accordance with FSFI after three months, using SPSS software. Results A statistically significant increase was noted in group B in domains of desire (pre-treatment 2.5±0.2 to 4.5±0.2 post-treatment), arousal (3.1±0.2 to 3.1±0.2 respectively), lubrication (3.4±0.3 to 4.3±0.3 respectively), orgasm (3.5±0.3 to 4.5±0.3 respectively), satisfaction (2.6±0.2 to 4.2±0.3 respectively) and pain (2.4±0.2 to 4.6±0.4 respectively) after three months treatment with tolterodine ER. In group A there were no statistically significant changes in pre and post treatment values (p>0.05). Total FSFI score for group B was significantly higher after tolterodine treatment (26.5±1.5) compared to pre-treatment values (17.4±1.4, p<0.01) and to control group A (17.7±1.2 and 17.9±1.5, p>0,05) respectively. Conclusions This preliminary study demonstrates that treatment of OAB with tolterodine ER was found to have positive effect on sexual function of patients with OAB.