Introduction. Ischemic heart disease is one of the most widespread cardiovascular diseases. In Republic of Moldova the total number of patients with ischemic heart disease is 30-40 thousand per 1 million population and is observed more of working age with important social value. Materials and method. An open randomized clinical trial involving 139 patients with chronic heart failure (107 men and 32 women) aged 37 to 81 years: 111 patients had angina pectoris of stable effort from different functional classes, and 28 – unstable angina pectoris, which include: basic treatment n = 43; basic treatment + meldonium (non-infarct) n = 52; basic treatment + meldonium (post-infarct) n = 35; basic treatment + meldonium, (aggravated) n = 9. Study groups were compared according to the frequency of using background (basic) drugs and meldonium. Statistical processing of the results was carried out in Statistics Software Package 9.0. Results. During the treatment, the increase of the nitric oxide level was registered even from the discharge stage, and in the second group being approximately at the same level as the initial stage. At the 3-month, nitric oxide level reached the normal level. There is an improvement of the endothelial dysfunction by the significant increase of the nitric oxide under the treatment at 6 months (in group I – 87.26±4.3 μM/L (p = 0.01), in group II – 95.33±10.85 μM/L). Conclusions. The inclusion of meldonium in the complex treatment of patients with stable angina increases the clinical efficacy of basic pharmacotherapy when prescribing meldonium, mainly due to increased antianginal actions.