The purpose of this study was to identify prospectively risk factors for pressure sores and to compare these results with a cross-sectional analysis in the same population. Medical records on all admissions to a chronic care hospital over a 13-month period were reviewed. Data on potential risk factors were abstracted from the initial history, physical examination, nursing assessment, and laboratory studies. Pressure sore status on admission and at three weeks was determined from a standardized from completed on all patients with a score. The cross-sectional analysis was performed by comparing patients with and without a pressure sore at the time of admission. The cohort analysis used patients initially without a pressure sore and monitored for a new sore at three weeks. Factors associated with pressure sores on univariate testing were entered into a stepwise logistic regression model. One hundred of the 301 admissions presented with a pressure sore. Factors significantly associated with the presence of a sore were altered level of consciousness (OR = 4.1), bed- or chair-bound (OR = 2.4), impaired nutritional intake (OR = 1.9), and hypoalbuminemia (OR = 1.8 for 10 mg/mL decrease). Of the 185 patients without a pressure sore, 20 (10.8%) developed a sore. Factors significantly associated with the development of a new pressure sore were a history of cerebrovascular accident (OR = 5.0), bed- or chair-bound (OR = 3.8), and impaired nutritional intake (OR = 2.8). Neither urinary nor fecal incontinence, nor the presence of hypoalbuminemia, was associated with sore development. We have prospectively identified risk factors for pressure sores.(ABSTRACT TRUNCATED AT 250 WORDS)