The aim of the present research is to determine the appropriate diagnostic methods to find out the affected fetuses with Down Syndrome in order to decrease as possible subjecting the pregnant women to invasive prenatal diagnosis . This is a Prospective – practical study, where /1137/ pregnant women at 13- 16 gestation weeks, ( age range: 20-42 years) were included. Biochemical screening of the pregnant women, ultrasound screening of the fetuses: nuchal translucency, nasal bone, which helped us to isolate the highrisk pregnancies for Down syndrome (the potential rate of incidence ≥ 0.4%). The screen positive group included 57 pregnant ( 5.01% ) . Amniocentesis and subsequently karyotyping was done to each woman in this group . We found out 4 affected fetuses from 5 ( 80%) , because the following up of the remaining pregnancies revealed a fifth affected newborn with Down syndrome. The early prenatal diagnosis of Down syndrome was possible in ( 80% ) by subjecting only ( 5.01% ) of pregnants to the invasive prenatal diagnosis .