Background: Control of hyperlipidemia is vital in CVD patients. Omega 3 fatty acids have desirable effects on serum triglyceride, thrombosis and arrhythmia but lead to increased level of LDL. Vitamin C can induce LDL receptor and catabolize LDL particle. The present study was conducted to determine the effects of administration of omega-3-fatty acid, vit C, and omega-3-fatty acid+vit C on LDL and other lipoproteins' profile and malonaldehyde in hyperlipidemic patients. Materials and methods: In a double-blinded, placebo controlled trial, 68 hyperlipidemic patients (TG and total cholesterol >200 mgldl) were randomly assigned to receive Vit C 500mgld, omega 3 fatty acid 191d, Vit C+omega 3 fatty acid (500mg and Ig per day), or placebo for 10 weeks. Fasting blood samples were collected at the beginning and at the end of the period, then, TG, TC, LDL, and HDL were determined enzymatically, and MDA and Vit C were measured calorimetrically. Results: The pattern of food consumption, socioeconomic and anthropoemetric status were not significantly changed during the study. There was a significant difference in the blood Vit C level at the end of the study, in comparison to the initial value in the Vit C (p<0.001) and Vit C+03Fas group(p<0.02), and also at the end of the study in Vit C+03Fas group in comparison to the control subjects (p<0.001). There was a significant difference in the serum TG at the end of study in the 03FAs group (p<0.002). In the Vit C group, a significant decrease was found in TC (p<0.004) and MDA (p<0.01), however, a well defined increase was noted in serum level of Vit C compare to the control group (p<0.01), meanwhile, significant decrease was showed in MDA compare to 03FAs group(p<0.03). At the end of the study, there was a significant decrease in TG/HDL ratio in 03F As group (p<0.04). Conclusion: Simultaneous administration of 03F As and Vit C had no beneficial effects on lipid profile of hyperlipidemic patients, however, Ig of purified 03F As daily for 10 weeks is a useful supplement for decreasing TG and TG/HDL without any increase in LDL and MDA.