Paraffin sections of condylomata acuminata removed from the lower genital canal were stained for papillomavirus antigen by th peroxidase-antiperoxidase test using a broadly cross-reactive antiserum. The antiserum was prepared by immunization of a rabbit with disrupted capsids of papillomavirus purified from a pool of plantar warts. Specific staining was seen as a brown granular reaction in the nuclei of the epithelial cells; this reaction occurred most consistently in the more superficial cells. Papillomavirus antigen was demonstrable in about half of the 50 specimens examined. The antigen was found in both flat and papillary lesions from the vulva, vagina, and cervix. The distribution of the antigen was widely variable and ranged from abundant in some specimens to patchy and sparse in others. In papillary lesions, antigen-positive cells were found characteristically at the tips of the epithelial fronds. The ability to detect the viral antigen in genital condylomas may help in understanding the pathogenesis of these lesions and in evaluating the role of papillomaviruses in th etiology of lower genital tract cancer.