Objective: To evaluate the role of activin A in pathogenesis and severity of pre-eclampsia & investigate whether oxidative stress might be the mechanism of increased secretion of activin A. Method: This was a case control study comparing cases of pregnancies complicated with hypertension ,with controls matched for gestational age . We studied serum levels of activiv A and malondialdehyde in 25patients with preeclampsia, 25 patients with pregnancy induced hypertension and 25 pregnant women with normal blood pressure. Results: Serum levels of activin A and malondialdehyde was higher in patients with pre-eclampsia than in patients with pregnancy induced hypertension and that of control group. There was highly significant correlation between serum levels of activin A and malondialdehyde in pre-eclampsia group and PIH group. Conclusion: levels of activin A increases in pre-eclampsia and oxidative stress might be the mechanism of increased secretion of activin A.