Thrombophilia has been an important topic in obstetrics, it is a hypercoagulable state of the blood due to heritable causes (as antithrombin, protein C, protein S, protein Z and factor V Leiden deficiencies, also activated protein C resistance, prothrombin G20210 mutation, thermolabile MTHFR, hyper-homocysteinemia, congenital dysfibrinogenemia and hyper-fibrinogenemia) or acquired causes (most important of which is antiphospholipid antibody syndrome). Thrombophilia and its effects has been an evident cause of maternal mortality in many countries over the past two-three decades. Maternal morbidity (as thromboembolism, pre-eclampsia, placental abruption and preterm labor…etc) and mortality (as due to pulmonary embolism) and also fetal IUGR and recurrent pregnancy loss are important sequele of thrombophilia. Screening of cases with thrombophilia, early diagnosis, thromboprophylaxis and active management can improve pregnancy outcome.