The detection of toxoplasma-specific antibodies is the primary diagnostic method to determine infection with toxoplasma in pregnant women. The present study aimed to evaluate the vertical transmission of anti-Toxoplasma gondii antibodies (IgM, IgG). ELISA is one of the easiest tests and most helpful technique in the diagnosis of toxoplasmosis. The 36 kDa toxoplasma gondii- (T.gondi) circulating antigen was isolated and purified from serumof toxoplasma infected mothers and umbilical cord samples of their neonates by electroelution. This antigen was used to detect the anti- T.gondii IgM and IgG antibodies in 95 serum samples from pregnant mothers and 95 umbilical cord samples collected from the umbilical cord of their neonates. Total anti-T.gondii IgM antibodies were detected in 32 (33.7%) serum samples with vertical transmission rate (9.4%). Total anti-T.gondii IgG antibodies were detected in 26 (27.4%) serum samples with vertical transmission rate (53.8%). The serodiagnosis of toxoplasmosis based on the detection of antibodies is not useful for the detection of toxoplasma vertical transmission. However, T.gondii circulating antigen was detected in 55 (58%) serum samples with vertical transmission rate (81.8%) in respect to antigen positive. Therefore, the detection of T.gondii circulating antigen in umbilical cord serum is considered as a good evidence for vertical transmission of this antigen.