Objectives: Pre-eclampsia affects approximately 5-8% of pregnant women. The aim of this study was to compare the serum level of Lactate dehydrogenase (LDH), Homocystein, Hemoglubin and platelet in pregnant women diagnosed as pre-eclampsia and a normal group in Gorgan city, Northeastern Iran from 2007-2008. Methodology: In this case control study, 50 cases of pre-eclampsia were compared with the control group women hospitalized in Dezyani hospital. Pre-eclampsia criteria were: Blood pressure more than or equal to 140/90 mm hg and Proteinuria greater or equal to 300 mg/ 24 hours urine sample in the third trimester. Hemoglobin, platelet, LDH and hemocystein were measured. Data were analyzed by the mean of SPSS-14 program & Chi-2 or t-student were used. Results: The difference of BMI and family incomes was significant between two groups (P-value0.01). Hemocystein level was more than normal range in five patients with pre-eclampsia (P-value<0.001). Conclusions: In this study, hemocystein level was significantly higher in pre-eclampsia patients but LDH, hemoglobin and platelet level had no significant difference