Objective: Myocardial disease without evidence of myocardial infarction is a frequent complication after cardiac surgery during cardiopulmonary bypass. Statins might be protective, but their efficacy has not been established in randomized trials. Methods: Two hundred patients undergoing coronary surgery were enrolled. They were randomized to rosuvastatin (20 mg/d, n ¼ 100) or placebo (n ¼ 100) starting 1 week before the operation. Troponin I, myoglobin, creatine kinase–MB mass, and high-sensitivity C-reactive protein were used as markers of myocardial injury, and their values were determined at baseline and at regular intervals after the operation. Electrocardiography and echocardiography were performed before and after the operation. Results: Myocardial disease was diagnosed when troponin I, myoglobin, and creatine kinase–MB mass values were above the upper normal limit without evidence of electrocardiographic changes, echocardiographic changes, or both. The percentages of marker level increase indicative of myocardial disease were determined in the placebo versus statin groups and were as follows: troponin I, 35%versus 65%(P