This is a preliminary report of an ongoing study to test the efficacy of intralesional injections of the antiviral drug cidofovir in adults with recurrent laryngeal papillomas in whom multiple other treatments have previously failed. This study has been designed to include 10 to 20 patients, a number sufficient to either prove or disprove the safety and efficacy of this agent. This report conveys information on the first three patients enrolled in the trial. Each patient received an overall dose of 5 to 10 ml of cidofovir, at a concentration of 4.17 mg/ml, intralesionally at 2- to 4-week intervals. The approximate volume injected into each wart was 0.2 to 0.5 ml. Biopsies of the lesion sites were obtained at the initiation and completion of therapy. No other treatment was given. Resolution of lesions was monitored by videolaryngoscopy and still photography 1 to 2 weeks after each treatment. In time, the lesions resolved in all three patients, although all three later experienced a minor recurrence. We conclude that intralesional cidofovir appears to be a promising new treatment for controlling--and perhaps at higher dosages curing--refractory laryngeal papillomas, while causing little or no injury to laryngeal structures.