Аннотация:The ability to use a spectrophotometric method to estimate the size and concentration of gold nanoparticles obtained by the method of laser ablation was considered. Gold nanoparticles synthesized by different methods have different physical and chemical properties of their surface. This can affect their optical properties in a colloidal solution. The results obtained in this work confirm the ability to use the spectrophotometric method to estimate the size and concentration of nanoparticles obtained by the method of laser ablation. It was demonstrated that it is optimal to estimate the concentration of nanoparticles using the spectrophotometric method at a wavelength of 400 nm. The determination of the size of nanoparticles by the absorption spectra in the ultraviolet and visible regions is possible for particles with a size of at least 11 nm.