Introduction. Liver transplant recipients suffer a high risk of developing cancer, mainly as a consequence of immunosuppressant treatment, although a variety of other factors are involved. Our purposes were to evaluate the frequency of de novo tumours and to determine predisposing factors. Material and Methods. We analyzed all of the transplantations performed during 1990, with a total of almost 700 cases. We analyzed the frequency of de novo tumors, their location, time since transplantation, survival, and recurrence rates and factors that may influence their appearance. Results. The series included 64 cases in 50 patients with a frequency of 7%. Skin tumors were the most frequent (39.06%), followed by those in the otolaryngologic (ear, nose, and throat) region (15.62%) and the lung (14.06%). The average time to progression between the transplantation and diagnosis was less than 4 years (47.74 months). The recurrence rate was 16%. The factors with the greatest influence on their appearance were age and gender of the recipient, alcohol consumption, and Child-Pugh score. Plasma transfusion was statistically, although not clinically, significant. Discussion. Our frequency of de novo tumors was consistent with that described in the literature. Despite some factors that influence their appearance, the main predisposing factor was immunosuppression and its duration.