Objective To compare the predictive validity of three pressure ulcer risk scales: the Braden scale; the Song and Choi scale; and the Cubbin and Jackson scale and to choose the most appropriate calculator for predicting pressure ulcer risk in the Surgical Intensive Care Unit (SICU) in South Korea. Design Non-experimental prospective study. Setting A 1,053 bed tertiary educational hospital in South Korea. Subjects 219 SICU patients at a hospital in South Korea from 1 November 2006 to 31 March 2007. Main outcome measures Sensitivity, specificity, predictive value positive and predictive value negative and the AUC (area under the curve) of the ROC (receiver operating characteristic) curve of the three pressure ulcer risk assessment scales Results Based on the cut-off points presented in this study, the sensitivity, specificity, predictive value positive and predictive value negative were as follows: the Braden scale (cut-off 14) had values of 92.5%, 69.8%, 40.6%, 97.6%, respectively; the Song and Choi scale (cut-off 21) had 95.0%, 69.2%, 40.8%, 98.4%, respectively; the Cubbin and Jackson scale (cut-off 28) had 95.0%, 81.5%, 53.5%, 98.6%, respectively. The AUCs of the ROC curve were 0.881 for the Braden, 0.890 for the Song and Choi and 0.902 for the Cubbin and Jackson. Conclusions The results of this research sample showed that the Cubbin and Jackson scale was most effective in predicting pressure ulcer risk compared to the other two scales in the SICU.