Prenatal screening of Toxoplasma gondii infection is controversial. The diagnosis is based on serological tests detecting IgM and IgG antibodies against T. gondii, but interpretation of these tests results is often confusing. It is commonly made retrospectively when serological screening indicates a possibility of recent infection. Most women have antibodies against T. gondii and serial testing is required only in monitoring of pregnancies where initial screening is negative. The introduction of Polymerase Chain Reaction (PCR) assay for detection of Toxoplasma gondii DNA in selected cases of pathologic pregnancies has permitted a more accurate and faster diagnosis of congenital toxoplasmosis infections.