The intensive care unit (ICU) population has a high risk of developing pressure ulcers. According to several national expert guidelines for pressure ulcer prevention, a risk assessment for every situation in which the patient's condition is changing should be performed using a standardized risk assessment instrument. The aims of this study were to (a) assess the number of patients who are 'at risk' for the development of pressure ulcer according to three commonly used risk assessment instruments in the intermediate period after cardiac surgery procedures, (b) assess which instrument best fits the situation of the ICU patients and c) decide if 'static' risk assessment with an instrument should be recommended. The modified Norton scale, the Braden scale and the 4-factor model were used in a convenience sample of 53 patients to assess the risk for development of pressure ulcer in the first 5 days (in ICU) after cardiac surgery procedures. The number of patients at risk were >60% by the 4-factor model, >70% by the modified Norton scale and >80% by the Braden scale. Sensitivity and specificity in all scales were not satisfactory. Forty-nine per cent (n= 26) of the patients developed a pressure ulcer in the operating room, 13% (n= 7) up to day 5 in the cardiac surgery ICU. Only 1.9% (n= 1) of the pressure ulcers were stage 2. The study concluded that the patients in the cardiac surgery ICU can be identified as at risk during the first 5 days after surgical procedure without continuously using a standardized risk assessment instrument in every changing condition. Individual risk assessment by a standardized risk assessment instrument is only recommended to enable initiation of preventive measures based on patient-specific risk factors.