Transplant recipients are at high risk to develop multiple cutaneous lesions after grafting. The frequency of the potentially oncogenic human papillomavirus (HPV) type 5 DNA was evaluated in cutaneous lesions taken from sun-exposed areas in transplant recipients (92 lesions and 5 samples from normal skin) and compared with a nontransplanted population (22 lesions and 7 samples from normal skin) using in situ hybridization and biotinylated probes to HPV types 1, 2, 5, 16 and 18. HPV type 5 DNA was identified in 8/92 cutaneous lesions of transplanted recipients: 3 warts, 1 case of seborrheic keratosis, 2 actinic keratoses and 2 keratoacanthomas. HPV type 5 DNA was not detected in 27 malignant tumors (8 basal cell carcinomas and 19 squamous cell carcinomas) from transplant recipients. HPV DNA type 5 was detected in only 1 case of squamous cell carcinoma from the general population. The presence of HPV DNA 5 was confirmed with Southern blotting in 2 out of 6 cases from transplant recipients. The reaction was negative with the squamous cell carcinoma from nontransplant recipients. These data indicate that the presence of HPV DNA type 5 is not very frequent; it can be detected with in situ hybridization and nonisotopic probe, which is easier to handle than Southern blot.