Introduction Severe obesity is most effectively treated with bariatric surgery. The resulting weight loss is expected to improve a variety of obesity-related conditions, including sexual dysfunction. Aim To analyze changes in the sexual function of women with obesity following bariatric surgery. Methods A prospective study was conducted between April 2015 and April 2016 involving 62 women with obesity who underwent Roux-en-Y gastric bypass. The Female Sexual Function Index (FSFI) was used to evaluate sexual function. Sexual dysfunction was defined as an FSFI score below 26.55. Patients’ clinical and demographic data were recorded. Sexual frequency of 12 different sexual positions was also evaluated. Main Outcome Measure Sexual dysfunction prevalence and the frequency of sexual positions before and 6 months after surgery. Results The prevalence of sexual dysfunction decreased from 62% before surgery to 19% 6 months after the procedure. There was a 19.2% improvement in the mean overall FSFI score ( P < .01). 6 months after surgery, the mean overall FSFI score had improved in all patients, with a statistically significant change being found in all 6 domains of the questionnaire ( P < .05). There was an increase in the frequency of 3 of 12 sexual positions evaluated. Conclusion Sexual function in women with obesity effectively improves after bariatric surgery. Favorable changes following weight loss included a significant reduction in the prevalence of sexual dysfunction and an increase in the frequency of different sexual positions during intercourse. Oliveira CFA, dos Santos PO, Oliveira RA, et al. Changes in sexual function and positions in women with severe obesity after bariatric surgery. Sex Med 2019;7:80–85.