Pressure Ulcers (PU) are ranked by the stage of presentation by NPUAP through I to IV, and since 2007 has included two new descriptors, in order to promote more reliable evaluation and classification of the stages of this type of injury. The research objectives were to identify nurses' knowledge about PU, in the aspects of identification, staging / classification and characterize this population. We used an instrument to collect data and applied to nurses in a public hospital on the Federal District, Brazil. The method used was descriptive and observational, with a convenience sample. Participants were 30 nurses, 63% female, mean age 35.8 years, 40% natural from Federal District, with experience in hospital and 9.6 years in average duration of training as nurse. Regarding knowledge about the new staging, only 7% were aware of the new nomenclature of the PU and 52% still used the previous classification. On the description or image remark about the stages of the PU, only in stage I we got the most correct answers, so for the other stages of the PU nurses were unable to describe or classify. It was evident that knowledge of nurses regarding the staging of the PU was outdated, so they should be encouraged to take training updates on the theme.