Purpose. Demonstrating diagnostic possibilities of stress computed tomography (CT) myocardial perfusion (CTP) and non-invasive fractional flow reserve (FFR) according to computed tomography angiography (CTA; FFRCT) in an evaluation of significance coronary artery lesions. Materials and methods. The first clinical case. A 56-year-old man with suspected acute coronary syndrome underwent stress CTP with transesophageal pacing according to the rest / stress protocol. Assessment of the coronary arteries revealed 70% stenosis of the proximal segment of the left anterior descending (LAD) artery, assessment of perfusion revealed transient anterior ischemia. During invasive coronary angiography (ICA), the presence of stenosis was confirmed, FFR was 0.68. The second clinical case. A 67-year-old man with a stable angina pectoris underwent CTA, according to which 70% stenosis of the proximal segment LAD artery was revealed. FFRCT was 0.75, when the author's mathematical tool was used. Subsequently, the patient underwent a stress-echocardiography, which revealed transient anterior ischemia. According to the ICA, stenosis in the LAD artery was confirmed, FFR was 0.7. The СT «Aqulion ONE 640 Vision Edition» (Toshiba, Japan) was used. Results. Clinical cases of using stress CTP and FFRCT as a diagnostic tool in chronic coronary syndrome are presented in this report. Discussion. Stress CTP and FFRCT are highly specific and accurate diagnostic tools, that can be used to detect coronary ischemia. Using these methods can help clinicians to optimize diagnostic work-up. FFRCT are more accurate test in comparison with stress CTP, that’s why further investigations, especially using Russian mathematical tool for the non-invasive FFR according to CTA are perspective and actual. Conclusion. In these clinical cases it was demonstrated that stress CTP and FFRCT can be used as effective d-tools in evaluation of significance coronary artery lesions. © 2020 Russian Electronic Journal of Radiology. All rights reserved.