The objective of this research was to know the role of F2-Isoprostane and nitric oxide in pathophysiology of preeclampsia. This research was a descriptive-observational study and the subject divided into 2 groups and inclusion criteria was full-filled (group I : 18 preeclampsia women – IA:9 mild preeclampsia/PER and IB:9 severe preeclampsia /PEB ; group II : 33 normal pregnant women). All subjects were measured the concentration of serum F2-Isoprostane by a competitive ELISA technique and the concentration of serum nitric oxide (NO) by non-enzymatic colorimetric assay. The datas analyzed statistically by calculating mean value and standard deviation of F2-Isoprostane and NO in 2 groups. Significancy level was tested with Student-t test in 95% CI. The mean value and SD of F2-Isoprostane in preeclampsia was 0,803 ± 0,521 ng/ml (PER : 0,707 ± 0,45 ; PEB : 0,899 ± 0,594), and in normal pregnancy was 0,557 ± 0,458 (p<0,001). The mean value and SD of NO in preeclampsia was 22,62 ± 3,79 µM/L (PER : 22,76 ± 3,89 ; PEB : 22,5 ± 3,91), and in normal pregnancy was 28,25 ± 12,49 (p < 0,001). There is a significant difference in the level of oxidative stress and endothelial dysfunction, while in preeclampsia is higher than in normal pregnancy.