Purpose. To determine the frequency of development of aspirin resistance in patients with coronary heart disease and to identify risk factors for the development of resistance to acetylsalicylic acid (ASA) in patients with coronary heart disease. Material and Methods: 96 patients were enrolled in this study with stable forms of ischemic heart disease who received a standard dose of aspirin 75 mg/day for a long time. Patients were divided into 4 groups according to the prescription of ASA. Group 1 consisted of patients who did not receive aspirin, the second group consisted of patients taking aspirin up to 1 year, the third group consisted of patients taking aspirin from 1 year to 5 years, and the fourth group included patients taking aspirin for more than 5 years. An addition, according to the results of determining aspirin resistance, the patients were divided into 2 groups. Platelet aggregation was measured using a laser analyzer: adenosine diphosphate (ADP) with 1.0 and 5.0 μmol was used. Resistance criterion: ADP ≥72% at 5.0 μmol. Results: 17.7% of patients who took aspirin in a standard dose of 75 mg/day were resistant to aspirin, and a third of them took aspirin for more than 5 years. According to the results of a study of platelet aggregation activity, the average degree of platelet aggregation with 5.0 μmol of ADP was 82.4% in patients with no reaction to aspirin. An inadequate response to aspirin was reliably often observed in women and the elderly (58.8% and 70.5%). When analyzing the results of routine laboratory studies in patients with aspirin resistance, there was a tendency to higher levels of cholesterol and glucose (p˂0.05). Possible risk factors for the development of ASA resistance are hypercholesterolemia and hyperglycemia, since aspirin resistance was more common in patients with diabetes (13 out of 17) and obesity (11 out of 17).Conclusion: High rates of ADP-induced platelet aggregation were obtained in ¼ patients with coronary heart disease. A