In this research, we measured the activity of paraoxonase (basal and activated) enzyme, and components of lipid status components (total cholesterol, LDL cholesterol, HDL cholesterol and Apo A I) in the serum of patients, undergoing bypass surgery. We also tested how the applied EKC affected changes of defined indicators. Measuring of all the given parameters was conducted prior to the operation, 90 minutes, 1.5 hour, 6 hours, 24 hours and 72 hours, on 29 patients (11 of them did undergo myocardium revascularization with the application of EKC, while the rest of them did not). Activity of paraoxonase (both basal and activated) changes significantly during the postoperative period, in relation to pre-operative values, p < 0.05. Total cholesterol concentration is reduced in both examined groups, regardless of the application of EKC. This trend is also accompanied by LDL cholesterol concentration. On the other hand, HDL cholesterol concentration during post-operative period does not indicate any significant statistical change in relation to pre-operative values, while we noticed difference with regard to EKC application, 90 minutes after surgery. This change of lipid status indicator is partly due to heparin, a stimulator of lipoprotein lipase that was applied during the surgery. Our conclusion is that lipid profile changes significantly after the bypass surgery, mostly regardless of the application of EKC.