This work was designed to study parameters of carbohydrate metabolism and insulin resistance (IR) in patients presenting with myocardial infarction (MI) and elucidate their relation to MI complications. Special attention was given to the relationship between disturbances of carbohydrate metabolism (DCM), the clinical course of myocardial infarction in the acute and cicatrization phases, characteristics of coronary arteries in the patients with and without diabetes mellitus (groups 2 and 1 respectively). Insulin resistance was documented in 83.2% of the patients. Multiple lesions in the coronary arteries were shown to be directly related to the immunoreactive insulin (IRI) level (r=0.277; p=0.0008) and HOMA index (r=0.304; p=0.0001). They were more common in patients with IR (86%; p<0.001). The clinical course of MI was more frequently complicated by early post-infarction angina, MI relapses, and heart failure (Killip functional class II) in the patients presenting with a combination of IR and DCM than in those showing normal sensitivity to insulin regardless of the characteristics of carbohydrate metabolism. It is concluded that the detection and correction of insulin resistance and disturbances of carbohydrate metabolism are the indispensable prerequisites for the successful prevention of myocardial infarction.