Reports of electrocardiographic abnormalities in association with myoglobinuria have been sparse and have included conduction disturbances, ST segment shifts, and T-wave changes. In many instances, these changes were noted in patients with underlying heart disease. We report a case of a 34-year-old woman with ST segment depression and T-wave inversion in the inferolateral leads during the acute episode of myoglobinuria. There was no demonstrable underlying heart disease, and there was parallel resolution of these ECG changes with myoglobinuria. We conclude that these ECG changes were produced by cardiac muscle involvement in a manner similar to that observed in skeletal muscle in myoglobinuria.