The aim of this study was to evaluate actual diagnostic profits of CKMBmass concentration in diagnosis of acute myocardial infarction (AMI) in the group of patients admitted to the Emergency Unit with stenocardia and comparison to CKMB activity test. The study carried out in a group of 53 patients admitted to the Emergency Unit of 5-th Military Hospital in Krakow. The study group consisted of 28 (52.8%) of patients with acute myocardial infarction and 25 (47.2%) with unstable angina pectoris. It was found that diagnostic sensitivity of both parameters (CKMBmass 70.8% and CKMB 67.8%) are equivalent for early diagnosis of acute coronary syndrome in the Emergency Unit.