Pre-eclampsia is an abnormal situation, characterized by hypertension and proteinuria in pregnancy due to widespread endothelial dysfunction. This disorder is a major cause of maternal morbidity and mortality in worldwide. Pay attention to significant incidence of pre-eclamptic toxaemia (PET) in pregnancy -as a physiologic phenomenon-, research about pathophysiology and invent of tests for early detection is important in Primary Health Care. Amongst, studies have been shown role of some angiogenic factors such as VEGF, PlGF (Placental Growth Factor) … in pathogenesis of PET. Many of these studies have indicated alleviation of VEGF and PlGF level in maternal blood circulation. These factors play a role in placental vessels development. In fact, serum that is got patients with disorder induces many physiological changes in endothelial cells indicating the presence of a circulating imbalance. Judging from these reasons, we examined relation between PlGF and PET risk in pregnant women. We studied 96 pregnant women (with one risk factor such as first pregnancy…) which were referred to Imam Hussein Hospital, SBMU, Tehran. In this study, PET has been associated with low levels (< 100 pg/mlit) of PlGF (P-value=0.007). Our study supports possible role of PlGF in pre-eclampsia occurrence. Results of this and other similar studies may use establishing early diagnosis test for PET. This can help to decrease maternal and neonatal morbidities and mortality.