Thirty-seven lesions from 29 patients with condylomata acuminata were comparatively studied by peroxidase-antiperoxidase (PAP) technique and routine histopathology. PAP staining demonstrated papillomavirus common antigen (PCA) mostly in the granular layer of the epidermis in 22 of 37 lesions (59%) of condylomata acuminata. Presence of PCA is closely correlated with the following histopathologic findings: 1) coarse keratohyalin granules; 2) perinuclear vacuolization or koilocytotic cells in the granular layer; 3) hyperkeratosis with focal parakeratosis. From these findings it is concluded that these histopathologic findings suggest the presence of PCA, and that the presence of papillomavirus may play a role in the formation of these histopathologic features of condylomata acuminata.