Cardiac hypertrophy is a physiological adaptive response by the heart to pressure overload. However, after prolonged periods, this initial adaptive response becomes maladaptive, leading to increased mortality and morbidity from heart failure. Recently, 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statins, have been shown to inhibit cardiac hypertrophy by cholesterol-independent mechanisms. Statins block the isoprenylation and activation of members of the Rho guanosine triphosphatase (GTPase) family, such as RhoA and Rac1. Since Rac1 is a requisite component of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, which is a major source of reactive oxygen species (ROS) in cardiovascular cells, the ability of statins to inhibit Rac1-mediated oxidative stress makes an important contribution to their inhibitory effects on cardiac hypertrophy.