Aim — to analyze cases of left main coronary artery stenosis after aortic root replacement. Material and methods. A total of 302 consecutive aortic root replacement procedures have been performed in our clinic from January 2012 till October 2017. In 5 cases the newly-formed left coronary artery stenoses were detected. All 5 patients had aortic root and tubular ascending aortic aneurysm, moderate or severe aortic insufficiency and left ventricle dilatation with preserved ejection fraction. Initially no lesion of the coronary arteries was observed. Results. At the in-hospital stage left main coronary artery stenosis was revealed in 3 cases (2 after Bentall procedure, 1 after David I procedure). In the last case circumflex artery occlusion was observed. Coronary angiography was performed due to elevated troponin I, ischemic ECG-signs and newly-diagnosed zones of impaired myocardial contractility. In the first two cases percutaneous coronary intervention (PCI) was performed, and in the last one — medication. In the fourth case after David I procedure intra-aortic balloon pump and temporary mechanical circulatory support (PLS system, Maquet) were used due to severe heart failure. The patient was weaned from the circulatory support on the 18th post-operative day. According to computed tomography left main coronary artery (LMCA) stenosis 50% was revealed, but the patient refused any further examination and was discharged. Three years later the patient was hospitalized to our clinic due to angina. Coronary angiography revealed LMCA stenosis 95% followed by PCI. In the fifth case in-hospital period was uneventful; however, angina occurred 11 months later. Severe LMCA stenosis and left anterior descending artery occlusion were revealed; following PCI was uneventful. Conclusion. Aortic root surgery may be followed by de novo coronary stenoses due to advanced coronary ostia dissection, bending and twisting of the coronary arteries and external causes. Possible local reaction to bioglue needs further analysis. Immediate visualization of coronary arteries must be performed in cases of myocardial ischemia and/or acute heart failure. Computed tomography may be useful within 2 months after aortic root surgery. PLS system is an effective method of circulatory support for severe heart failure.