Sera from 2790 0-15 aged infants and children were titrated for antibodies to Toxoplasma gondii by indirect immunofluorescent test. Maternal-derived antibodies were found at high rates in the first six months of life (32.9%). The positivity rate declined during the second semester of life (7.5%) and increased again with time (7.8% between 1 and 5 years, 11.2% between 5 and 10 years, 14.4% between 10 and 15 years). No statistically significant differences were found between the sexes. IgM specific antibodies were found at a titre of 1:32 or greater in 41 subjects (1.5%), who also exhibited IgG antibody titres ranging from 1:512 to 1:1024. Our results indicate a remarkable diffusion of toxoplasma infection in our area.