A programme for the prevention of congenital toxoplasmosis in Slovenia involving the screening of pregnant women for Toxoplasma infection is presented. Of 21,270 pregnant women screened for toxoplasmosis between, 1996 and the end of 1999, 13,987 (66%) were seronegative, 7,151 (34%) seropositive and 132 had primary infection; ≈ 9/1,000 women were at risk of acquiring the primary infection. One hundred live-born infants of primary infected women were available for follow-up. Nine infected but asymptomatic children were born to mothers who were screened and treated in time and two congenitally infected babies were born to mothers in whom infection was detected too late in pregnancy and who therefore received no adequate treatment. It is suggested that the results obtained in this study outweigh the cost of screening for toxoplasmosis in pregnancy. Pregnant women should always be tested at the beginning of pregnancy and, in cases of seronegativity, should be re-tested in the second and third trimesters of the pregnancy. Toxoplasma primary infected pregnant women and neonates should be treated as soon as possible. However, long-term follow-up of children born to primary infected women would be necessary for an accurate evaluation of the effectiveness of the screening because of the possibility of late onset of symptoms.