Relevance. Cardiovascular diseases (CVDs) remain one of the leading causes of mortality worldwide. In recent years, significant attention has been given to L-arginine, a conditionally essential amino acid that serves as a key precursor of nitric oxide, a critically important mediator of vascular function. Dysregulation of L-arginine metabolism and the development of endothelial dysfunction play a significant pathogenetic role in the development and progression of CVDs. Objective. This review aims to systematize current data on the role of L-arginine in the regulation of vascular tone, its impact on endothelium-dependent vasodilation, and to assess the potential application of L-arginine in the intensive care of cardiovascular diseases. Material and methods. A comprehensive analysis of the results of in vitro and in vivo experimental studies, as well as clinical trials focused on examining the influence of L-arginine on endothelial function, hemodynamic parameters, coronary blood flow, and other cardiovascular system parameters was conducted. Particular attention was given to analyzing the molecular mechanisms of NO-mediated action of L-arginine and its interaction with the arginase enzyme. Results. L-arginine contributes to enhancing endothelium-dependent vasodilation, reducing blood pressure, and can have a positive impact in cases of coronary heart disease, heart failure, and atherosclerosis. It is important to note that the effectiveness of L-arginine therapy can be modulated by the level of ADMA, an endogenous inhibitor of nitric oxide synthase (NOS). Conclusion. L-arginine represents a promising therapeutic agent for use in the intensive care of CVDs, especially in patients facing potential ischemia-reperfusion syndrome. To determine optimal therapeutic strategies, including dosage selection and identification of target patient groups, further large-scale, placebo-controlled clinical studies are necessary.