Intentional carbon monoxide (CO) poisoning has become the commonly used method of suicide in some Asian countries. The objective of this study was to identify the predictors that impact the outcome of intentional CO-poisoned patients with acute respiratory failure. Materials and Methods: This is a retrospective observational study of 796 consecutive patients diagnosed with acute CO poisoning that presented to the emergency department (ED). Patients who were CO poisoned with intentional exposure and acute respiratory failure were enrolled and divided into two groups. The poor outcome group consisted of in-hospital death, the presence of persistent neurological sequelae, and the presence of delayed neurologic sequelae. The good outcome group consisted of other enrolled patients. Demographic and clinical data of the two groups were extracted for analysis. Results: A total of 148 patients were enrolled in this study. Of the eligible subjects, 67.6% (100) were identifi ed with positive toxicology screening results. On arriving ED, parameters associated with patients with a poor outcome included hypotension, myocardial injury, prolonged lag times from the fi rst ED arrival to initiation of hyperbaric oxygen therapy, higher white blood cell count, and higher serum levels of blood urea nitrogen, creatine kinase, and troponin-I (P < 0.05). Positive toxicology screening result did not relate to the outcome. Multivariate analysis showed that the myocardial injury was an independent factor for poor outcome (odds ratio, 2.750; 95% confi dence interval, 1.168-6.474; P = 0.021). Conclusions: Myocardial injury is an independent predictor of in-hospital death and neurologic sequelae in patients with intentional CO poisoning and acute respiratory failure.