Abstract –The present electron microscopic study visualizes adherence of Treponema denticola, the most common treponeme of the gingival crevice in man, to human epithelial cells in vitro. The number of organisms adhering to the cells increased with increase in the treponemal concentration from 106cells/ml through 108cells/ml. Epithelial cells immediately after mitosis were particularly rich in treponemes. The number of adsorbing treponemes was reduced after pretreatment of the epithelial cells with hyaluronidase. The epithelial cells showed no predilection site of treponemal attachment. Treponemes attached preferably by their ends. Intracellularity of treponemes was not regularly attained. Treatment with ruthenium red, acidic bovine albumin or hyaluronidase indicated presence of acidic mucopolysaccharides on the treponemal and epithelial cell surfac