Each year an estimated 4900 cases of primary Toxoplasma infection occur in pregnant women in France, a country with a high prevalence. Since 1992 all pregnant women at risk of Toxoplasma infection have been required to undergo monthly serological testing. This case-control study, the first of its kind in France, was undertaken to identify risk factors for Toxoplasma infection during pregnancy, with a view to improving primary prevention among non-immune pregnant women. A total of 80 pregnant women who seroconverted to Toxoplasma were matched with 80 pregnant women who had repeatedly negative tests. The women were interviewed by telephone, using a standardized questionnaire, to determine socio-demographic characteristics, exposure to possible risk factors and the type of information on prevention received during pregnancy. The risk factors for Toxoplasma infection included in a multivariate analysis were poor hand hygiene (OR = 9.9; 95%CI: 0.8-125), consumption of undercooked beef (OR = 5.5; 95%CI: 1.1-27), having a pet cat (OR =4.5; 95%CI: 1.0-19.9), frequent consumption of raw vegetables outside the home (OR = 3.1; 95%,CI: 1.2-7.7) and consumption of undercooked lamb (OR = 3.1; 95%CI: 0.85-14). Receipt of documentary advice on prevention was associated with a lower risk of infection. Prevention campaigns among pregnant women in France could be improved and should focus on eating habits, hand hygiene and cats.