Uptake of carbon particles through the epithelium and their transportation route in the canine palatine tonsils were investigated by light microscopy. Reticular and non reticular regions were distinguished in both oral surface and crypt epithelium. Particle ingestion was peculiar to the reticular epithelium. The ingested material was first transported mainly in phagocytosed form to the subepitelial connective tissue and following into the deeper regions, to the bases of lymphoid follicles through the interfollicular tissue. Any free or phagocytosed particles were not observed at the germinal centers of the follicles. It was concluded that the tonsils might operate as a primary sampling area for restricted number of antigens which the animal is exposed. On the other hand, they may contribute to the common mucosal immune system via trafficking of both antigen primed lymphocytes and antigen phagocytosed macrophages those were frequently observed in the luminae of venous and lymphatic sinuses, located at the center of the tonsil.