Background: Group B Streptococci (GBS) is the leading cause of septicemia, meningitis andrnpneumonia in neonates. Maternal colonization with GBS is the principal risk factor for early-rnonset of invasive GBS disease in infants. GBS is now recognized to be an important cause ofrnmaternal and neonatal morbidity and mortality in many parts of the world; however, it has beenrnlittle studied in Ethiopia.rnObjectives: To determine the prevalence of GBS colonization, antibiotic susceptibility patternrnand identify risk factors related to GBS among pregnant women attending antenatal care clinicsrnof Health Institutions in Addis Ababa, Ethiopia.rnMethods: A cross sectional prospective study was conducted from May-August, 2014.rnConsented participantsâ€™ information was collected using structured questionnaire. A total of 281rnvaginal swabs were collected by consecutive sampling technique and inoculated into ToddrnHewitt Broth and later sub cultured on 5% blood agar for isolation of GBS. Antimicrobialrnsusceptibility testing was performed according to the criteria of the clinical and laboratoryrnstandard institute (CLSI) guidelines 2013 by disk diffusion method. Data was entered andrnanalysed using SPSS version 20.0 software. Chi-square test and binary logistic regressionrnanalysis were used. A 95 % CI and P- value of < 0.05 were considered statistically significant.rnResult: The overall prevalence of GBS colonization among pregnant women was 14.6%rn(41/281). GBS colonization was significantly associated with health institutions and inverselyrnrelated with history of contraceptive use (P