BACKGROUND AND OBJECTIVES: The pathological findings of Non-Q wave myocardial infarction(NQMI) on ECG did not always correspond to subendocardial infarction(SEMI). The purpose of this study was to evaluate the diagnostic validity of ECG for SEMI by myocardial contrast echocardiography (MCE) in the patients with acute myocardial infarction(AMI). MATERIALS AND METHODS: The study population was 84 patients who underwent MCE under the diagnosis of AMI. MCE was performed by intracoronary injection of sonicated Hexabrix into the infarct related artery and SEMI was diagnosed by inspecting endocardial defect with epicardial enhancement on MCE. RESULTS: (1) Among 19 NQMI cases, 7 cases showed SEMI with MCE score 0.5, 11 cases with score 1, and 1 case with score 0. Among 65 Q-wave MI(QMI) cases, only 5 cases showed SEMI. (2) 7 cases who had NQMI with SEMI showed LV wall motion recovery at follow-up echocardiography except 1 case. Whereas, of 5 QMI cases who had SEMI, only 1 case improve LV wall motion. CONCLUSION: NQMI on ECG does not always imply SEMI on MCE, but the absence of pathologic Q wave in the patients with SEMI is thought to be a predictive factor of the recovery of LV wall motion.