Growth factors as vascular endothelial growth factor (VEGF), produced by the endothelial cells, take an essential part in pathological and physiological angiogenesis. The possibility of angiogenesis modulation by application of laser radiation may contribute to the improvement of its use in this process. Thus, the aim of the study was to investigate the influence of low-level laser therapy (LLLT) on the proliferation of endothelial cells, secretion of VEGF-A and presence of soluble VEGF receptors (sVEGFR-1 and sVEGFR-2) in the medium after in vitro culture. Isolated human umbilical vein endothelial cells (HUVECs) were irradiated using a diode laser at a wavelength of 635 nm and power density of 1,875 mW/cm(2). Depending on radiation energy density, the experiment was conducted in four groups: I 0 J/cm(2) (control group), II 2 J/cm(2), III 4 J/cm(2), and IV 8 J/cm(2). The use of laser radiation wavelength of 635 nm, was associated with a statistically significant increase in proliferation of endothelial cells (p = 0.0041). Moreover, at 635-nm wavelength, all doses of radiation significantly reduced the concentration of sVEGFR-1 (p = 0.0197).