Background Preeclampsia is an idiopathic disorder of pregnancy characterized by proteinuric hypertension; hydralazine is an arterial vasodilator antihypertensive drug. Nifedipine is a calcium channel blocker antihypertensive drug. Objective To compare the effect of intravenous hydralazine and oral immediate release nifedipine capsule in patients with severe preeclampsia in their 3rd trimester of pregnancy and compare the early perinatal outcome. Material and Methods A prospective cohort study set at Sulaimani Maternity Teaching Hospital, Sulaimani, Iraq, throughout period of January first 2015 to September first 2015. The study includes 50 patients diagnosed with sever preeclampsia (blood pressure ≥ 160/110 mmHg and > 1 gram proteinuria) in the third trimester of pregnancy, who admitted to Emergency Department of Sulaimani Maternity Teaching Hospital from January, first 2015 to September, first 2015. Patients had been divided into two groups, the first 25 patients had received hydralazine and the second 25 patients received nifedipine. The blood pressure and fetal heart rate recorded before and after the treatment, the target blood pressure: Systolic blood pressure < 160 mmHg and diastolic blood pressure < 110 mmHg. Results Both drugs were ultimately effective in reaching the therapeutic goal because there were no failures requiring crossover in either study group. Patients received intravenous hydralazine achieved the therapeutic blood pressure more rapidly in (38.0±14.0) minutes (mean±SD) as compared with (51.3±23.9) minutes who received oral immediate release nifedipine. P=0.05. Both drugs had no effect on fetal heart rate but they had many maternal side effects especially with hydralazine which associated with more palpitation than nifedipine (12% versus 8%). In mode of delivery, 72% of women from hydralazine group and 52% of women from nifedipine group their pregnancies are terminated by caesarean section, while 36% of women from nifedipine group and 20% of women from hydralazine group were delivered vaginally. Conclusion Both drugs are efficient in controlling the blood pressure in sever preeclampsia and no significant difference in perinatal outcome. Nifedipine needed longer period but less number of doses to reach the goal blood pressure. Because the nifedipine’s oral bioavailability and less frequent side effects, it more preferable anti-hypertensive therapy in emergency cases compared to the hydralazine.