This descriptive correlational study had the goal of exploring if relationships existed between the level of knowledge of nurses concerning pressure ulcers, certain nurses' characteristics and the preventive care they applied. A multi-method approach was taken using a questionnaire to measure the level of knowledge of nurses (n = 256) and chart audits (n = 235) to identify the preventive care applied. The results show that the level of knowledge of the nurses is insufficient. They also show a correlation between a higher level of knowledge and (i) the sector of activities in which the nurses are working, (ii) the training periods provided by the university hospital centre, and a (iii) good perception by the nurses of their level of knowledge. However, training on its own cannot guarantee the provision of quality health care, as there is a wide discrepancy between what nurses know and what they put into practice.