To measure the prevalence of seropositivity for toxoplasmosis in pregnant women and evaluate its association with maternity age, skin color, place of residence and education.A cross-sectional study in 1,261 pregnant women cared for at the maternity ward of Hospital Nossa Senhora da Conceição was performed from June to October and in December 2000. Serological tests for toxoplasmosis were performed during their pregnancy or delivery. The variables considered were place of residence, skin color, education and serum tests for toxoplasmosis (IgG and IgM). Microparticle Enzyme Immunoassay method (MEIA) was used.The prevalence of seropositivity for toxoplasmosis in the pregnant women studied was of 59.8% (95% CI: 57.0% - 62.5%). An increase in seropositivity in relation to the mother's age was observed (p = 0.012). On the other hand, a higher educational level was found to be a protective factor against toxoplasmosis (p < 0.001). The hypothesis that the proportion of pregnant seropositive women would increase the farther they lived from capital cities was not confirmed (p = 0.750). Differences regarding race were not observed (p = 0.228). In the multivariate analysis, maternity age presented a linear association with the increase of seropositivity, even after adjustment for education, place of residence and skin color.The prevalence of seropositivity in the pregnant women studied is high and justifies the adoption of some primary and secondary preventive measures, until subsequent studies provide greater evidence concerning the rationalization of the diagnostic and therapeutic techniques regarding toxoplasmosis in pregnant women.