Human papillomavirus (HPV) DNA was isolated from a clinically diagnosed flat wart and proved to be related to HPV2. The isolate showed 55% cross-hybridization with HPV2a. A physical map of restriction enzyme cleavage sites differed completely from those of HPV2a and HPV2b. The new HPV2 subtype, which will be classified as HPV2c, was found to be very prevalent in common warts.