--- - |2+ Abstract Objectives To investigate the association between body mass index (BMI) and sexual functioning in gynaecologic cancer patients. To determine the association between socio‐economic deprivation and sexual functioning. Methods This is a prospective cohort study on women undergoing surgery for suspected or proven gynaecological cancer between September 2014 and February 2016 in the Royal Cornwall Hospital Trust. Patients were invited to participate by completing the Female Sexual Function Index (FSFI) at three time points: preoperative, 3 months postoperative, and 1 year postoperative. A semiparametric model of the FSFI score was used to establish the association between BMI and sexual functioning. Results A total of 257 patients were approached of which 166 patients were included. Fifty‐two patients (33.8%) were overweight (BMI, 25‐29.9 kg/m2), 44 (28.6%) were obese (BMI, 30‐39.9 kg/m2), and a further 20 (13.0%) morbidly obese (BMI ≥ 40 kg/m2). Overweight and obese women reported improved sexual functioning compared with normal‐weight women in endometrial, ovarian, and vulvar cancers. Among cervical cancer, worse sexual functioning was seen in women with an increased BMI; however, this was not significant. Younger age was associated with improved sexual function, and sexual functioning was better postoperatively for all patients compared with preoperatively. There was no evidence of relationship between deprivation and sexual functioning in gynaecological cancer patients. Conclusion Higher BMI is associated with improved sexual functioning in endometrial, ovarian, and vulvar cancer; however, this was not seen in cervical cancer patients. There is no evidence of correlation between deprivation and sexual functioning. - Psycho-Oncology, EarlyView.