The aim of the article is to conduct analysis of accumulation and biodistribution of gold nanoparticles in the structural and functional areas of mesenteric lymph nodes of white rats. Particular attention is paid to the size and duration of oral administration. Material and Methods: Dark field microscopy with Leica DM 2500 microscope has been used to assess biodistribution of gold nanoparticle. The histochemical reaction of silver amplification with silver lactate by Danscher has been used to confirm gold nanoparticles identification. Results: It has been found that regardless of the duration of administration gold nanoparticles of 1-3 nm have not been detected by these methods in the lymph nodes. Gold nanoparticles of 15 and 50 nm have been found out in the form of clusters in the cytoplasm of macrophages and lymphocytes mainly in the mantle zone of lymphoid follicles and brain strands. Conclusion: It has been established that the gold nanoparticles of 15 and 50 nm has been detected in the form of clusters in the cytoplasm of macrophages and lymphocytes