Aim: The objective of the present work was to study effects of low-level laser irradiation on the endothelial function and selected parameters of microcirculation in the patients presenting with rheumatoid arthritis. Material and methods: This study included 132patients at the age varying from 18 to 85 years presenting with rheumatoid arthritis. They were divided into 2 groups. The patients of the main group (n=102) underwent daily intravenous laser blood irradiation during 10 days. The control group was comprised of 30 patients. Laser therapy was performed with the help of a laser therapeutic device "Matriks - VLOK" (Matriks, Russia) using alternation of two radiating heads: Kl-VLOK-63 (wavelength 0,63 µm, output power at the lightguide tip 1,0-1,5 mW, pulse frequency 80 Hz, for 15 minutes) and Kl-VLOK-365 (wavelength 0.365 µm , output power at the lightguide tip 1,0-1,5 mW, for 5 minutes) in the continuous emission regime. The parameters of interest were measured before and after the treatment. The overall duration of intravenous laser irradiation of blood was 10 days without a break for the weekend. Results: The data obtained suggest the improvement of the endothelial function and the microcirculation indices.