Aim Pressure injuries as an indicator measuring the quality of nursing care and patient safety is a major health care problem worldwide. The aim of this study was to assess the knowledge, attitude and behaviour of nurses in preventing pressure injuries. Design Descriptive cross-sectional study. Methods This descriptive cross-sectional study enrolled 214 registered nurses in Iran. Patient satisfaction was assessed using pieker pressure ulcer knowledge test, attitude towards pressure ulcer tool and behaviour of pressure ulcer questionnaire. Data analysed by SPSSv.24 applying descriptive and inferential statistics. Results The mean scores of knowledge, attitude and behaviour of nurses on the prevention of pressure injury were 27.24 (SD 5.23), 38.55 (SD 6.43) and 51.24 (SD 7.54), respectively. There was a correlation between knowledge, attitude and behaviour with the history of pressure injury training. Also, there was a significant relationship between knowledge with educational level and attitude with work experience. Knowledge, attitude and behaviour of nurses were in moderate level. Necessary measures to overcome problems such as the availability of pressure reducing equipments, motivating the nurses, eliminating the shortage of nurses and empowering nurses by holding practical workshops are important in providing patients safety.