HMG CoA reductase inhibition effect of rice bran extract and its fractions were examined. Successive extraction was done by using ethanol, followed by successive fractionation using n-hexane, dichloromethane, ethyl acetate, and water for fractions with highest activity. Anti HMG CoA reductase activity of the extract and its fractions were determined spectrophotometrically by NADPH oxidation, using HMG-CoA as substrate. Rice bran extract and its fractions showed more than 50% inhibitory effect on enzyme activity. The extract of rice bran showed 51.44% inhibitory effect on HMG CoA reductase activity. The water fraction from ethanol extract gave the strongest activity (64.54% inhibition). Kinetic study of the enzyme was performed on one concentrations of water fraction (0.05 mg mL-1). These active fractions showed uncompetitive inhibition in Lineweaver-Burk plot analysis. Under standard condition, Km value for non-inhibitor was Km 331.45 mm and Vmax value was 1.3 mm min-1, while with inhibitor Km value was 56.57 nmm and Vmax 0.3 mm min-1.