Toxoplasmosis is a cosmopolitan protozoan infection. Data regarding risk factors for the post-natal acquisition of Toxoplasma gondii infection in childhood are limited. We conducted a serological survey for T. gondii IgG antibodies and associated risk factors in 1,217 children 4-11-yr-old from Salvador, Brazil, using a commercial ELISA kit; antibodies were found in 17.5% of the children. Age (OR = 2.18; 95% CI: 1.50-3.17) and maternal schooling level (OR = 0.62; 95% CI: 0.42-0.92) were negatively associated with infection. A greater number of siblings (OR = 1.53; 95% CI: 1.12-2.09), cat at home (OR = 1.54; 95% CI: 1.06-2.24), house with non-treated piped water (OR = 2.54; 95% CI: 1.22-5.31), and the absence of a flush toilet at home (OR = 1.45; 95% CI: 1.04-2.01) were positively associated with T. gondii infection. Our data suggest that low socioeconomic levels and poor hygiene habits are important factors in favoring T. gondii infection.