Glucosamine has a major influence on the impairment of some metabolic mechanisms in the human body. As shown in vitro experiments, it takes part in inducing mechanisms of insulin resistance. Therefore, the purpose of our study was to evaluate glucosamine levels in the serum of patients who suffered myocardial infarction (MI) and who either had or didn't have diagnosed type II diabetes in relation to healthy people. The levels of glucosamine, immunoreactive insulin, C-peptide, glucose and lipid indexes were measured in venous blood in investigated patients. In patients with MI without diabetes the highest concentrations of glucosamine, insulin and C-peptide were noted as compared to the results obtained from other groups of patients. In patients with diabetes, on the other hand, the highest glucose levels were noted as compared to the results of other patients. There were no statistically differences of lipid indexes between two groups of patients following MI. A negative correlation between glucosamine levels and glucose concentrations in patients without diabetes may suggest that glucose does not directly determine glucosamine levels. The returning of insulin levels to normal in patients with hyperinsulinemia (antidiabetic drugs) may play a role in the lowering of glucosamine induced peripheral insulin resistance.