Background. Laser biostimulation uses the direct effect of low-level laser (LLL) radiation on cellular processes without causing heat or tissue damage. The goal of our research was to evaluate the possibility and safety of using LLL in patients with advanced multi-vessel coronary artery disease (CAD) in whom revascularization is impossible. Material and methods. We enrolled 18 patients diagnosed with severe multi-vessel CAD who were not qualified for transcutaneous or surgical revascularization. Other inclusion criteria included stenocardial symptoms in CCS class II-III and complete pharmacological treatment. All patients were subjected to complete clinical examinations, basic biochemical examinations, radiological exams of the chest cavity, resting EKG, a walking test, stress EKG, and full echocardiogram with flow evaluation. The patients received LLL treatments using B1 helium-neon lasers. The exposure time was 15 minutes per session, 6 days a week for one month. After two 4-week laser therapy cycles with a month interval between, the baseline parameters were measured again.Results. No systemic or local side effects from laser radiation were observed, nor any complications. There was improvement in CCS class, lower blood pressure, longer 6-minute walk, greater output, and fewer low ST segments during the stress EKG; however, the differences did not achieve the level of statistical significance.Conclusions. Further research is needed. based on a larger population and a project design that includes a placebo group.