An investigation was carried out to evaluate some of the etiologic factors of inflammatory hyperplasia. The lesion was found in 97 out of 700 patients (13.9 per cent). It occurred in the palate and was always associated with the wearing of dentures, especially those which had relief areas in the palate. It was possible to associate the lesion with constant wearing of the dentures. The results indicate that the cause of inflammatory papillary hyperplasia is complex, and it seems to occur only in susceptible subjects when the tissues are irritated by local factors. The lesion is treated by reducing the inflammation and removing the papillae. The construction of new prostheses and the education of patients in oral hygiene and the care and maintenance of their dentures are essential.