Acute myocardial infarction (AMI) is a major cause of morbidity and mortality in deleveloped  countries and an important health problem in developing countries. Generally, hyperlactatemia is an anaerob metabolism product as a result of indeaquate tissue oxygenation. Myocardial ischemia will cause decrease of ATP formation from phosporylation oxydation and pyruvate conversion into lactate in sitosol with very high speed that cause tissue lactate accumulation. Hyperlactatemia is a metabolic stress marker and its severity level associated with increase morbidity and mortality. Serial lactate levels measurement will give more advantage than only one time. The aim of this study is to investigate hyperlactatemia as mortality predictor 30 days post AMI. Method: This study was a prospective cohort observational study and 121 acute myocardial infarction patients were included as subjects with consecutive sampling. Lactat levels measurement used capillary blood when the patients admitted and 2 hours after using Accutrend lactate meter. ROC curve was used to determine hyperlactatemia level. Patients were followed until 30 days to evaluate mortality. Results: The result of this study was hyperlactatemia with lactate levels ≥ 4,4 mmol/L was a threefold mortality predictor 30 days after AMI (HR=3,33, 95% CI 1,084-10,210, p value= 0,036) and Killip class (HR: 2,814, 95% CI: 1,786-4,435 p <0,001) and hemoglobin levels  (HR: 0,810, 95% CI: 0,672-0,978 p = 0,28) as a confounding factors. Conclusion:  Hyperlactatemia is a mortality predictor 30 days after acute myocardial infarction. Beside of that, Killip class and hemoglobin levels are  confounding factors.