PurposeSexually transmitted infections (STIs) can be transferred from one person to another through sexual contact. STIs lead to substantial morbidity and mortality and affect many different aspects of human life, including quality of life, sexual health, reproductive health and even the health of newborns and children. Despite of high rates of STIs in prisons, there are not sufficient screening, prevention and treatment programs to control STIs transmission among prisoners in Iran. This study aims to evaluate the prevalence of STIs among incarcerated women in Iran for the first time, using the active case finding strategy.Design/methodology/approachThis is a cross-sectional study conducted on 438 incarcerated women in a prison in Tehran, Iran, from 2017 to 2018. A total of 438 prisoners were screened by active case findings for STI symptoms, then evaluated by complete genital and anal examination, followed by molecular testing.FindingsA total of 189 (43.2%) prisoners announced vaginal discharge, while 194 (44.3%) individuals had vaginal discharge in the genital examination. In the cervical examination, 137 individuals (31.3%) had abnormal findings, of which 83 (18.9%) individuals had cervicitis, 40 (9.1%) individuals had cervical erosion, 38 (8.7%) individuals had cervical prolapse and 17 (3.9%) individuals had bleeding originated from the cervix.Originality/valueThis study showed that it is possible to set up a system in which the diagnosis, follow-up and treatment of prisoners with STIs can be actively performed. Educating prisoners about signs and symptoms, risk behaviors and prevention routes of STIs, as much as regular screening of prisoners, and adequate treatment can help control the STIs prevalence among prisoners and in the general population.