The aim of this study was to determine the prevalence of the genital mycoplasmas cervical colonization among the pregnant women from the Eastern Croatia and to evaluate its correlation with the demographic and the behavioural risk factors. Study was conducted from March 2010 to April 2011 at the Microbiology Department of the Institute of Public Health for the Osijek-Baranja County. The study included 456 pregnant women in the first and the second trimester of pregnancy. Demographic data and data on their possible risk behaviour during the lifetime were collected with the usage of an anonymous questionnaire consisting of the 16 questions. The Mycoplasma Duo kit test was used to diagnose the mycoplasma infections. Due to the fact that the results were generally similar for the women with U. urealyticum or M. hominis and in order to dichotomize the analyses, 164 (36%) participants with U. urealyticum, M. hominis or both were considered positive, whereas 292 (64%) participants without U. urealyticum or M. hominis were considered negative. A higher genital mycoplasmas prevalence was statistically significantly associated with the younger group of the pregnant women (16-29 y), 5 or more sexual partners during lifetime and the age on the first intercourse < or = 16. The study has showed that both the demographic and the behavioural risk factors were associated with the higher genital mycoplasmas colonization in the observed population.