Objective : Determining the prevalence and aetiology of sexually-transmitted infections and endogenous infections in women of childbearing age having lower genital tract infection symptoms and describing the pertinent risk factors. Materials and methods: This cross-sectional Colombia, Bogota, Colombia. study was carried out at three outpatient healthcare. Etiologic diagnosis was made using Nugent's criteria for bacterial vaginosis, blood agar culture for Candida and wet mount for T. vaginalis . The In-pouch culture technique was used for T. vaginalis, the polymerase chain reaction for C. trachomatis and N. gonorroheae and serological tests for syphilis (RPR, TPHA) and HIV on a sample Network for Perinatal & Reproductive Health, Portland, Oregon, USA. of the aforementioned population. Results: 1,385 females were recruited in 2010. 115 (8.3%) were sex workers. An LGTI was confirmed in 731 (52.7%); 560 (40.4%) had an endogenous infection and 170 (12.3%) a sexually-transmitted infection (STI). The most frequent aetiology were bacterial vaginosis (39.6%), candidiasis (11%), C. tra chomatis (9.7%) and N. gonorroheae (1.4%); Trichomona was detected by wet mount (0.8%) and culture (1.2%), as were syphilis (0.8%) and HIV (1 case). Sex workers had a higher risk of having an STI (2.0 OR; 1.2-.3 95% CI), as were younger females (28 ± 7.8 cf 32 ± 8.9) (p = 0.001) and alcohol users (2.6 OR; 1.4-4.5 95% CI). Conclusions: Aetiology was identified for 52.7% of the females who consulted for lower genital tract infection symptoms; bacterial vaginosis was the most common and Chlamydia the most frequent sexually-transmitted infection. No specific aetiology was identified in almost the same number of females (47.3%), even when using gold-standard diagnostic technology for each microorganism.