Sexual dysfunction is a common and distressing consequence of breast cancer (BC) treatment. In the present study, we investigated the sexual functioning of BC patients and its association with women's personal characteristics and cancer treatments. In this cross-sectional study, sexual function was assessed using the Female Sexual Function Index (FSFI). The health-related quality of life (HRQOL) was measured using the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and its breast module BR-23. Of the 235 participants approached, 216 participants were included in the study. Of these, 63 patients reported no sexual activity in the last month and thus were analyzed only in relation to the sexual desire domain of FSFI. A total of 154 (71.3 %) patients were classified with hypoactive sexual desire disorder (HSDD). From those patients reporting sexual activity in the last month, 63.3 % (97 out of 153) were classified with sexual dysfunction. Using hierarchical logistic regression, the variance explained (change in R ) by the addition of body mass index (BMI) and mild to moderate physical activity in the prediction models of sexual dysfunction and HSDD were 6.8 and 7.2 %, respectively. Age, BMI, and physical activity were independently associated with sexual dysfunction and HSDD. Additionally, BC patients with sexual dysfunction reported lower scores on global HRQOL, role functioning, and fatigue. Based on our findings, BC survivors should be encouraged to practice regular physical activity and to lose weight in order to avoid sexual dysfunction. However, future clinical trials are needed to confirm these findings.