The authors compared the informative value of 39 criteria of myocardial infarction with ECG registration using the standard 12-lead system (ECG-12), 24 criteria according to Frank's orthogonal system (OECG-F), and 32 criteria according to the new 4-lead system (ECG-4). 127 patients with myocardial infarction (MI) were examined. The sensitivity of the most informative ECG-4 criteria of MI was higher (44.4%) than OECG-F (39.4%) and ECG-12 (38.6%). With the application of quantitative ECG-4 criteria, signs of MI were detected in all cases diagnosed by experts using the ECG-12 system. In view of the considerable simplicity of its registration technique, the ECG-4 system can be recommended for the mass screening ECG examinations aimed especially at detection of MI.