The incidence, diagnosis, and impact on surgical management of myocardial contusion (MC) are incompletely defined. During a 12-month period, all patients admitted to a Level I trauma center with blunt trauma were prospectively evaluated for MC (n = 1,110). Those with anterior chest wall contusions, sternal or anterior rib fractures, or pain/tenderness of the anterior chest (n = 140, 13%) underwent immediate and daily ECG, and CPK isoenzymes were measured at admission and every 6 hours in the first 24 hours. Eighty-nine of these patients underwent gated ventricular angiography (GVA) and 66 underwent two-dimensional echocardiography (2D ECHO). MC was considered present if either: 1) CPK-MB was greater than or equal to 5% of total CPK, or 2) an abnormal admission ECG reverted to normal before patient discharge. Fifty-six patients (5% of admissions, 40% of those with apparent chest trauma) were positive by one or both criteria. Thirty patients (54%) were positive by CPK alone, 23 (41%) by both CPK and ECG, and three (5%) by ECG alone. Of the 53 with elevated CPK-MB, 14 (26%) were normal on admission with the remainder becoming elevated in the first 24 hours. 2D ECHO was abnormal in only three of 21 positive patients (14%), and GVA was abnormal in only three of 40 positive patients (7%). Surgical procedures requiring general anesthesia were performed in 37 (66%) of the positive patients. No significant arrhythmias developed under general anesthesia.