To evaluate first trimester screening test parameters in epileptic patients using anti-epileptic drugs.We retrospectively evaluated first trimester screening test results of 23 epileptic pregnant women using anti-epileptic drugs with a control group consisting of 92 healthy pregnancies. The anti-epileptic drugs used in this study were carbamazepine, levatiracetam, valproic acid and lamotrigine. Single drug or multi-drug regimens were used according to the clinical conditions. Patients with any known chronic or acute disease and drug usage were excluded from the study. Comparisons were performed via Mann-Whitney U test.First trimester screening test biochemical markers were compared and maternal serum PAPP-A MoM values were found to be similar in study and control groups while β-hCG MoM values were significantly higher in pregnancies using epileptic drugs (p: 0,737 and p < 0.001, respectively).Biochemical first trimester screening test results may be affected by anti-epileptic drug usage, which may lead to misinterpretation of the risk level. Thus, validation of MoM values should be necessary in order to obtain optimal results.