F2 Isoprostanes, derived from the non-enzymatic peroxidation of arachidonic acid, are considered to be reliable biomarkers of oxidative stress in the human body [1]. In this study, we aimed to develop a sensitive and selective method for the determination of total 8-Iso-Prostaglandin F2α (8-iso-F2α) in human plasma. The plasma samples were hydrolyzed and the total lipids were extracted in ethyl acetate. The lipid extracts were purified to NH2-cartridges and then F2 isoprostanes were eluted with ethyl acetate/methanol/acetic acid (10/85/5, V/V/V) [2] and then derivatizated with N,O bis(trimethylsilyl)trifluoracetamide [3]. GC-MS/MS analysis was performed on Agilent Technologies 7000A Triple Quad and 8-iso-F2α-d4 was used as internal standard (IS). Chromatographic separation was performed using HP-5 ms 30 m × 0.25 mm x 0.25 μm film film thickness column and detection was performed on a triple quadrupole tandem mass spectrometry using electron impact ionization in positive mode and multiple reaction monitoring (MRM). The monitored MS/MS ion transitions were m/z 481→391.2 and m/z 485.4→395.2 for 8-iso-PGF2α and IS, respectively. A good linearity was observed in the concentration range 50-2000 pg/ml. The lower limit of detection (LLOD) was 15 pg/ml and the lower limit of quantification (LLOQ) was 25 pg/ml. The validated method was applied to quatification of F2 isoprostanes in human plasma from coronary artery disease (CAD) patients from the Cardiology Department, Elias Emergency Hospital Bucharest, in 4 groups with stable angina (SA), unstable angina (UA), a month after myocardial infarction (MMI) and subjects at risk for CAD without cardiac events (HR).In conclusion, we developed a sensitive, selective and reproducible method for 8-iso-F2α determination in plasma. Results showed that the levels of 8-iso-PGF2α from UA and MMI pacients plasma were not significantly increased compared to HR and SA plasma patients.