The distribution and morphology of macrophages were studied by immunohistochemical and electronmicroscopic methods in three diseases of the palatine tonsils: tonsillar hypertrophy, recurrent tonsillitis and tonsils with focal infection. We confirmed the presence of two types of macrophages in the tonsils, a monocyte-macrophage cell line and dendritic cells with subtypes, Langerhans' and interdigitating reticulum cells. In the lymphoepithelial symbiosis area and in the subepithelial area, the monocyte-macrophage cells and the dendritic cells had similar distributions and densities. Since these two types of cells were sometimes in contact with each other, they may function in close cooperation. In tonsils with focal infection, there were fewer dendritic cells in the lymphoepithelial symbiosis area, and the germinal centers were less well developed than in the other tonsillar diseases. These findings suggest that in tonsils with focal infection, insufficient amounts of antigen may be presented by the dendritic cells to helper T-lymphocytes.