Cidofovir is a nucleoside analog of deoxycytidine with a strong activity against a broad spectrum of DNA viruses, including human papillomavirus. The first objective was to evaluate efficacy of cidofovir for the treatment of cutaneous viral warts, recalcitrant after conventional therapies or where the surgery approach is difficult for their location or extension. Second, the present authors propose to point out possible local and systemic side effects consequent to treatment. Two-hundred eighty patients affected by recalcitrant cutaneous viral warts, were treated with intralesional cidofovir 15 mg/mL once a month. The present authors stated that candidates were those who had made before at least two other treatments reported in the guideline for management of cutaneous viral warts. In 276 cases, warts completely cleared: 158 of those have a follow-up period longer than 12 months and 118 have a follow-up of 6 months. On the average, 3,2 injections were enough to solve the problem. Local side effects consisted of pain and burning sensation during the injections; itching, erythema, and post-inflammatory hyperpigmentation were observed. No cases of systemic side effects were noted. The treatment was well tolerated, and the warts were completely cleared without relapses. Intralesional cidofovir is emerging as an effective therapeutic alternative for warts that are unresponsive to conventional treatments.