This research was performed with the purpose of being acquainted with the frequency of onset of subprosthetic stomatitis in a large group of individuals and to determine some causal variables derivative of personal customs and habits of using prosthesis. The universe of study was represented by all the patients carrier of denture-plate for six months or more, who attended to 36 stomatologic clinics during a period of three uninterrupted weeks. A total of 6,302 individuals was examined and 2,952 of them were recorded as affected by subprosthetic stomatitis, for a rote of 46.84%; corresponding 50.47% to female sex and 39.96% to male sex. The most involved decade of life was that of 30 years, for 49.8%, and higher affection was observed in individuals using prosthesis with acrylic base, accounting for 48.45%. The largest amount of lesions, 63.04%, corresponded to clinical grade I. Of the individuals who estimated at the beginning of using fixed prosthesis, that such prosthesis were suitable and well fitted, 47.14% presented alterations. Of the individuals examined, 83.38% had the habit of sleeping with prosthesis, and 51.07% of them was affected by lesions.