Introduction. Transplant recipients are at increased risk for cutaneous warts. We have investigated the delay of their onset warts and some possible risk factors for their occurrence. Patients and methods. Clinical data were summarized on a standard question and examination sheet. Warts were diagnosed on clinical grounds and course duration assessed on patients' report. Immunosuppressive therapy and HLA group were collected from clinical transplantation records. An actuarial curve was used to evaluate the delay of onset of warts. To compare associated risk factors among the two groups (patients with warts and patients without warts) at 1 year and 3 years following transplant, single variate analysis was performed. Results. At the time of transplant, the prevalence of warts was 16 p. 100. It was increased with the duration of immunosuppression: 23 P, 100 at I year, 35 P. 100 at 3 years, 45 P. TOO at 5 years and 54 P. 100 at 7 years. Warts were multiple and principally localized on the hands. Transplant recipients without cutaneous warts 3 years after transplant had less intensive Immunosuppressive therapy than the group with cutaneous warts. No association was found between age, sex, H LA markers, actinic keratosis and wart onset. Discussion. The prevalence of warts increases with the duration of transplantation. Cutaneous warts are generally multiple and have a chronical course without spontaneous remission. More intensive immunosuppressive therapy increases their occurrence. This trial cannot evaluate the association between carcinoma and warts, on the basis of our study, there is no relationship between actinic keratosis and warts, nor HLA markers and warts.