Selection of patients for preventive measures to protect against pressure ulcers relies on clinical scales and provider judgment, which vary widely. Our objectives were to: (a) identify risk factors by clinical classification and report demographic differences in pressure ulcer risk and (b) develop criteria for identification of high-risk patients. Patients with pressure ulcer as a discharge diagnosis were identified from the 2003 Nationwide Inpatient Sample (NIS). The effect of discharge diagnosis was examined using the Agency for Healthcare Research and Quality Clinical Classification Software (CCS). Multiple regression analysis for survey data was used to assess risk factors. The 2003 NIS listed 94,758 with a discharge diagnosis of pressure ulcer, identified as International Classification of Disease-9 code 707.0-707.09, for an overall incidence of 143 per 10,000. Forty-five CCS discharge diagnoses were present in at least 5% of these patients and 28 of these CCS diagnoses had odds ratios >2.0. African-American race and advanced age were identified as risk factors for pressure ulcer diagnosis. Disorders of skin integrity, organ system failure, and infection were found to be broad categories of risk factors as well. Using the NIS, risk factors for pressure ulcer including diagnoses and demographic factors have been identified.