Background:Pressure ulcers increase hospital stays and treatment costs due to their complications. Therefore, recognizing factors that contribute to pressure ulcer risk are important to patient safety.Objective:To evaluate the association between the scores of the Waterlow, Braden, and Norton scales and clinical and social characteristics in critically ill patients.Method:A cross-sectional study of 78 patients in an adult intensive care unit of a university hospital in Northeastern Brazil was conducted from July to December 2015. Data included social and clinical information and the risk factors of the Braden, Norton and Waterlow scales. Data were analysed by the descriptive and inferential statistics.Results:Most of the participants were female, adults and elderly people with brown skin colour, low education levels and insufficient income. Most of them showed a high risk for developing pressure ulcers using the three evaluated scales. Age, smoking status, diabetes and hypertension were associated with scores on the Waterlow, Braden and Norton scales.Conclusion: Age, use of the tobacco, diabetes and hypertension were associated with the risk of pressure ulcers in ICU patients.