Introduction: Cardiogenic shock (CS) is the leading cause of mortality in patients with acute myocardial infarction (AMI). Inflammatory response seems to be common response in patients with AMI, especially those with CS. We have therefore conducted a study to determine diagnostic and prognostic utility of interleukin 6 (IL6) levels in the cohort of patients with cardiogenic and septic shock (SS) and in a control group of patients with uncomplicated AMI. Methods: In this prospective study 71 patients fulfilled the inclusion criteria: 30 patients with cardiogenic shock, 21 patients with septic shock and 20 patients with ST elevation myocardial infarction (STEMI). Plasma levels of IL6 were measured at 8 time points. The main endpoint was 3 month mortality. Results: We have shown that the highest IL6 levels during the first week were recorded in patients with septic shock with peak value at admission. The maximum level of IL6 was detected between 12 to 24 hours after the onset of Ml among patients with cardiogenic shock. According to Receiver operating characteristic (ROC) statistics levels of ILfi > 357 pg/ml at admission (AUC 0.730, p = 0.031) were typical for patients with CS in comparison with control group of STFMI patients. Values of IL6 > 1 237 pg/ml at admission and > 1 071 pg/ml at 24 hours (after admission?) were typical for thouse in septic shock in comparison with CS patients. We found only a non-significant trend of IL6 for the prediction of mortality in the cohort of CS patients for levels > 1 854 pg/ml (AUC 0.769, p = 0.066) sampled 12 hours after admission. There was no association of plasma levels of IL6 with mortality in septic shock patients. Conclusions: Patients with cardiogenic shock demonstrated more pronounced cytokine response as evidenced by increased levels of IL6 compared to patients with uncomplicated STEMI, Levels of IL6 peaked in SS patients at admission, in CS patients 12-24 hours after admission. In daily clinical practice routine measurement of IL6 levels for prediction of prognosis both in cardiogenic and septic shock are of little value mainly due to significant interindividual variability of IL6 values.