Assessment of the risk of toxoplasma infection during pregnancy in the female population of the Geneva area, and of the risk of congenital toxoplasmosis, has shown 9 cases of toxoplasmosis for 1000 pregnancies and 3.5 congenital infections for 1000 newborn infants. These results show that the prevalence of toxoplasma infection has been decreasing constantly during the 15 years of study, but that the risk of infection during pregnancy and of congenital infection has remained steady.