Lipids have an important role virtually in all aspects of life-serving as hormone or hormone precursors, aiding in digestion, providing energy storage and metabolic fuels, acting as functional and structural components in cell membranes and forming insulations to allow nerve conduction or to prevent heat loss. Increased cholesterol is a causative factor in the etiology of atherosclerotic diseases. About 60% of plasma cholesterol is normally found in LDL fraction; 25% in the HDL fraction; while the rest of Cholesterol is present in VLDL variety. High density lipoproteins are also mainly Cholesterol esters. They are scavengers of Cholesterol and their function is to transport Cholesterol from the tissues to the Liver. HMG-co A reductase inhibitors are widely used in the treatment of hypercholesterolemia due to their efficacy in reducing blood LDL-Cholesterol. Here we report the Cholesterol lowering effect of generic Simvastatin products in comparison with the Original brand Zocor. Method: The generic drugs used in the present study were Atcol & Limitrol of Atco & Pharmevo laboratories respectively. The serial blood samples were collected after drug administration every 4 weeks for 12 weeks. Results: After the administration of drugs for 12 weeks; there was no significant difference statistically between the Original brand Zocor and the Atcol & Limitrol treated groups. All the drugs were well tolerated and only minor side effects nausea & dizziness were observed in some patients. Conclusion: It can be concluded from this study that no significant difference can be observed as regards the efficacy & safety of these drugs. The efficacy & safety of the generic & brand drugs is almost the same & there is no statistical difference between them.