BackgroundHuman papillomavirus (HPV) and Trichomonas vaginalis (TV) infections are the most common STIs. The latter has contributed to a variety of adverse outcomes for both sexes. Moreover, in Brazil, epidemiological studies on patients with STIs are limited. Therefore, this study aimed to determine the prevalence of TV and its association with HPV in women undergoing cervical cancer screening. MethodsWomen with a normal cervix were recruited from a community-based cervical cancer screening program. Gynecological examinations were conducted and questionnaires were provided. Vaginal canal and uterine cervix samples were collected and tested for the presence of TV and HPV DNA. ResultsThe overall prevalence of HPV DNA was 45.68%; among these, 27.1% had a co-infection with TV (p = 0.001). The presence of TV was associated with an increased risk of HPV (p = 0.0001) and previously identified cytological changes (p = 0.0001). ConclusionsWe concluded that a TV infection is associated with an HPV infection of the cervix as well as with the cervical cytological abnormalities. Further studies could reveal the mechanisms by which these two organisms interact at the cellular level, with control for shared behavioral risk factors. This research is in agreement with Resolution No. 466/2012 of the National Health Council and has the Research Ethics Committee of the Hospital Universitário Presidente Dutra, from Universidade Federal do Maranhão, under opinion number 76328917.5.0000.5086.