Lymphoid cell subsets were studied in biopsy specimens of uninfected and infected ear canal epidermis, tympanic membrane, cholesteatoma epithelium, and middle ear and antrum granulation tissue. All specimens showing uninfected squamous epithelium, including those of cholesteatoma membrane, contained only a few lymphoid cells. Biopsies of infected squamous epithelium showed enhanced Ts/c activity in the subepithelial layer. Granulation tissue showed normal Th/i activity. B-cells and NK cells appeared in small numbers. Lymphoid cell subset analysis is indicated in ears reconstructed with allograft material to detect signs of rejection. It is of little value in cases of chronic inflammatory middle ear disease which have not previously been operated upon.