Human papillomavirus (HPV) type-16 DNA sequences were found in 26/53 (49%) and HPV type-18 in 5/53 (9%) of penile cancers. In only one specimen was HPV18 found on its own. HPV16 sequences were integrated into the host cell chromosomes although some monomeric and oligomeric free forms of DNA were detected in a few tissues. HPV18 was, as far as detectable, free and unintegrated in all tissues tested. HPV16 DNA was also detected in 40% of cases of carcinoma of the cervix in 19 women from the same social groups as the males. The viral DNA in the female cases was a mixture of integrated and free forms. The DNA binding protein (ICSP 11/12) of herpes simplex type 2 (HSV2) was not detected in 10 penile cancers tested with a monoclonal antibody.