he aim of our study was to investigate the cellular composition of the lymphoid structures of the human intrahepatic bile ducts. Materials and Methods: The object of the study was the lymphoid structures of the walls of the intrahepatic bile ducts obtained from 45 cadavers of different ages. Lymphoid nodules in the walls of the intrahepatic bile ducts were investigated by T. Hellman’s method. The microanatomy of lymphoid structures was studied on microscopic preparations. Microscopic preparations were stained according to Van Gieson, with hematoxylin-eosin, methylene blue. The digital data obtained during the study was subjected to statistical processing. Results: A macromicroscopic study of lymphoid formations in the intrahepatic bile ducts showed that lymphoid formations in the walls of these organs are represented by lymphoid nodules and diffuse lymphoid tissue. The peripheral contours of the lymphoid nodules are clearly defined. Histologically, the cellular composition of lymphoid nodules and diffuse lymphoid tissue was studied. In the mucous membrane and in the submucosa, small, medium sized lymphocytes, and large lymphocytes, macrophages, plasma, reticular, mast cells, cells in a stage of mitosis, degeneratively altered (destructive), and other forms of lymphoid cells are determined. Conclusions: According to our data, newborns have not only lymphoid nodules, but also a typical cellular composition in the lymphoid tissue, which has a completely “mature character”. The results of morphometric studies showed that in early childhood there is a high percentage of small, medium, large lymphocytes, macrophages, cells with signs of mitosis.