Assessing sexuality is a difficult task, hence used tools should be straight forward and easy to use.To assess sexual function in mid-aged Ecuadorian women.In this cross sectional study, 904 otherwise healthy women 40-59 years completed the short 6-item Female Sexual Function Index (FSFI-6) and a general socio-demographic questionnaire containing personal/partner data. Internal consistency of the tool was also assessed.Median age of the whole sample was 49 years, 51.1% were postmenopausal, 43.8% lived at high altitude, 12.6% used hormone therapy (HT), 58.5% presented hot flushes, 43.5% were abdominally obese and 80.8% had a partner. Overall, 72.4% of surveyed women reported sexual activity (n=655/904) with 65% of these presenting total FSFI-6 scores equal or below 20 the calculated median (lower sexual function). A 10.2% of those having a partner were sexually inactive. Internal consistency of tool was high (Cronbach's alpha=0.91). Total FSFI-6 scores positively correlated with coital frequency and female and partner educational level and inversely with female age, waist circumference, hot flush intensity and partner age (bivariate analysis). Multiple linear regression analysis determined that lower scores (lower sexual function) were related to high altitude, history of sexual abuse, sedentarism, hot flush intensity, partner age and sexual dysfunction whereas partner educational level, coital frequency and female parity were significantly related to higher scores (better sexual function).As assessed with a consistent, short, and easy to use tool lower sexual function of this mid-aged series was related to several female and partner factors. More research with this tool is warranted.