Familial Mediterranean Fever (FMF) is the most common hereditary monogenic autoinflammatory disease. In this study we aimed to document whether FMF affects the biochemical components of first and second trimester combined aneuploidy screening tests including serum free beta human chorionic gonadotropin (?-hCG), placenta associated plasma protein-A (PAPP-A), unconjugated estriol (uE3), total hCG and alfa-fetoprotein (AFP). In this prospective case control study, a total of consecutive 59 singleton pregnancies, 29 of with FMF and other 30 healthy women, were followed from the first trimester to end of the pregnancy. Most of pregnant women with FMF (86.2%) were under treatment with colchicine. The markers PAPP-A, free ?-hCG and the nuchal translucency (NT) thickness were examined at 11-13 weeks. Serum samples for AFP, uE3 and total hCG were obtained at 16-19 weeks after detailed examination. There were no cases of fetal chromosomal anomaly in neither of the groups. Both first-and second trimester marker levels were not significantly different in absence of aneuploidy or neural tube defects in FMF and control group. No difference was seen for NT measurements. False-positive rate for Down syndrome was comparable between the groups using a term risk cut-off level of 1/250. Pregnant with FMF should be reassured about the not altered levels of first-and second trimester marker. Therefore readjusting the serum markers used for Down syndrome screening is not advised. Future trials of larger scale are needed to assess any need for readjustment of the risk in the patient population with FMF.