Photodynamic therapy (ALA/MAL-PDT) is indicated for the treatment of actinic keratoses, for superficial, nodular basal cell carcinoma and for Bowen's disease; there is evidence that PDT can be active also against bacteria, viruses and fungi. The new indications for PDT include many types of viral skin infections human papilloma virus (HPV)-related as verrucae of feet and hands, Condylomata acuminata, periungueal warts, epidermodysplasia verruciformis, but also viral skin lesions non HPV related as molluscum contagiosum and herpes simplex can be successfully treated. The use of PDT in HPV infections is due to its anti-inflammatory and antiproliferative skills: in the lesions treated there is a release of cytotoxic radicals which damage keratinocytes infected by HPV, inducing their selective apoptosis and necrosis. The PDT application in this field of lesions is safe and successful; in comparison with the other techniques it has less side-effects and less recurrences, but the most important property is that it is not-invasive: it means a reduced risk of infections and excellent cosmetic results.