Aim: Quadruple test is used for Down's syndrome screening in the second trimester of pregnancy. The aim of this study was to investigate differences in quadruple test parameters between pregnancies achieved by assisted reproductive treatments (ART) and spontaneous conception. Materials and methods: We retrospectively compared levels of alfa-fetoprotein (AFP), unconjugated Estriol (uE3), inhibin-A and hCG and also screen positive test results. Results: Levels of all quadruple test parameters were statistically significantly increased in ART pregnancies when compared to spontaneous pregnancies, AFP was 1.4 +/- 0.74 and 1.16 +/- 0.53, (p = 0.001), uE3 was 1.10 +/- 0.37 and 1.00 +/- 0.28, (p = 0.004), hCG was 1.56 +/- 1.04 and 1.26 +/- 0.76, (p = 0.001), inhibin A was 1.38 +/- 0.76 and 1.08 +/- 0.57, (p = 0.001), screen positive tests were nearly doubled (4.8% and 8.4%). Conclusions: Increased screen positive test results and quadruple test parameters in ART pregnancies may lead to unnecessary amniocentesis.