Statins, which are inhibitors of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, are considered as one of the most important drugs and the drug of choice for reducing an abnormal cholesterol level. Statins are normally used to decrease the risk of coronary heart disease (CHD), but they tend to be associated with liver adverse effects. The objective of this prospective study was to investigate the effect of atorvastatin therapy on the liver function in patients with CHD. Study comprised of 66 newly diagnosed CHD patients who were selected from UNRWA clinics in the Gaza Strip. The patients were clinically examined and treated with atorvastatin (10 - 40 mg/day). A questionnaire was used to collect the data concerning patient’s characteristics. Total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), liver enzymes tests such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and total and direct blood bilirubin were measured before starting treatment and after 3 and 6 months of treatment. The results showed a significant increase in the mean values of ALT, AST, total bilirubin and direct bilirubin levels after 3 months then decreased after the next 3 months, but they were higher than the baseline with insignificant association.