Background: The study was a comparative study of cervico-vaginal bacterial flora changes in women using copper-T380A contraceptive device and levonorgestrel-IUS in Ibadan: a two-centre clinical cohort study. The normal bacterial vaginal flora of women may change following insertion of a foreign body in the genital tract and may predispose to cervico-vaginal infection. Intrauterine contraceptive devices in the genital tract are foreign bodies that have the tendency to alter the normal vaginal flora of women and may predispose to cervico-vaginal infection. The pattern of vaginal flora change may be pathogenic leading to symptomatic infection and in some cases asymptomatic vaginal infection. Aim: The aim of this study was to determine the change in bacterial cervico-vaginal flora of women using CuT380A in comparison with those using LNG IUS in Ibadan and their predisposition to cervico-vaginal infections. Methodology: The study which was carried out between March and August 2016 involved 130 women recruited from two family planning clinics in University College Hospital and Adeoyo Maternity Teaching Hospital in Ibadan. Sixty-six women were in the CuT380A group while 64 women were recruited in the LNG-IUS group. All the participants met the inclusion criteria. Endocervical and high vaginal swabs were performed on each group of women without clinical evidence of infection before insertion of the devices, then at 3months and at 6months. The study had both clinical and laboratory parts. Their clinical symptoms during each review were noted. The swabs were processed in the microbiology laboratory.