This study, designed to investigate the blood lactate and pyruvate levels in AMI, was carried out on 41 patients. Based upon the localization of AMI, the patients were studied under anterior AMI (n=17), anteroseptal AMI (n=9) and inferior AMI (n=15) groups. Left ventricular failure developed in five patients with anterior AMI and in one patient with anteroseptal AMI. Cardiogenic shock developed in two patients with anterior AMI. Lactate and pyruvate were analysed in the blood samples drawn 24-48 hours after AMI. CPK, CPK-MB, AST and LDH activities were determined in the sera of blood samples drawn within 6-24 hours of AMI. Enzymatic methods were performed for lactate and pyruvate analyses, kinetic methods of CPK and LDH activities, immunoassay for CPK-MB and colorimetric method for AST. A significant difference was found between the pyruvate values of anterior and anteroseptal AMI groups and also between anterior and inferior AMI groups (0.05>p>0.02, 0.02>p0.01 respectively) Lactate/pyruvate ratio was found to be significantly higher in the anterior AMI group in comparison to the inferior AMI group (0.05>p>0.02). The cardiac enzyme activities were found to be significantly higher in the anterior AMI group. Increased blood lactate/pyruvate ratio might be considered as a predictor of left ventricular failure and shock occurence in AMI and also as an indicator of insufficient tissue oxygenation, might serve as a determinant in choosing the correct intervention therapy.