A series of 65 male sexual partners of 65 women attending an STD clinic in Bologna, Italy for examination and treatment of genital human papillomavirus (HPV)-infections during 1990-1991, were examined using peniscopy and surgical biopsy, the latter being analysed by light microscopy, in situ hybridization (ISH) and polymerase chain reaction (PCR) for HPV DNA. A detailed medical and sexual history was recorded from all men. Of the 65 men, 17 (26.2%) gave a history of a previous STD. The male partners with previous genital condylomata (14, 21.5% of men) were significantly associated with the detection of HPV DNA in the current lesions; 21.4% (3 of 14) and 10.2% (5 of 51) in those with and without previously treated condyloma, respectively. On colposcopy, 63 (96.9%) men presented with an abnormal pattern, the vast majority (49 of 65, 75.4%) showing an acetowhite lesion, and only 12 (18.5%) lesions being classified as condyloma acuminatum. HPV DNA was found, however, in only 4 of 12 (33.3%) condylomas by ISH and PCR, and in 4 of 49 (8.2%) and 6 of 49 (12.2%) acetowhite lesions by ISH and PCR, respectively. In a total of 41 (63%) patients, the biopsy was classified as non-HPV on light microscopy. HPV DNA detection rate was significantly higher in all morphologically HPV-suggestive lesions, compared with the non-HPV where ISH was invariably negative. PCR, however, disclosed HPV DNA in 4 of 41 (9.8%) cases. PIN (I or II) was present in 6 of 65 (9.2%) men.(ABSTRACT TRUNCATED AT 250 WORDS)