The occrrence of pressure ulcers (PU)is a reality in many health care services and they are charecterized for being frequent lesions found in serious hospitalized patients or in institutionalization places for long periods. The general aim of this study was analyzing the incidence of PU in elderly people living in Long Staying Instituitions (LSI).It is a prospective cohort quantitative study; 94 elders attended the sample. The results showed a global cumulative incidence of 39.4%. Thirty seven (77.1%) elders developed single ulcer; the preferential location were the malleolus(27.1%) and the ischium (25.0%) and the stage I PU were the most frequent ones (66.7%). Female sex (62.8%) and the caucasians (68.19%)prevailed, with an average age of 79.06± 9.6. They presented an average BMI ranging from 20.93±4.9, with a predominance of urinary diseases (58.5%), use of neuroepileptics/psycothropics(52.1%). The previous ulcer was present in 28.7% of the elderly studied. Female sex and previous ulcer presence were confirmed as predictive for the development of PU, according to the logistic regression(r2= 0.311). As we can conclude, this study contributes not only for the infomation about the incidence of the PU in institutionalized elderly, as for the systematization of methods that can repplied in other centers and in future investigations. Keywords:1. Pressure ulcer 2.Incidence 3. Elderly 4. Long Staying Institutions.