The relationship between operating room (OR) table surfaces and skin integrity was examined. Preoperatively, patients (N = 505) were rated for pressure sore potential (Hemphill); postoperatively, skin condition was assessed. Skin changes were more likely with a standard mattress only or with surgery longer than 2.5 hr. The overlay was more effective than the foam and gel or standard foam mattresses for preventing pressure sore formation. Factors predictive of pressure sore development included surgery of 2.5+ hr, 40+ years, vascular disease, and a preoperative Hemphill value of 4+. Patient characteristics, surgical experience variables, and OR table surfaces are determinants in pressure sore development.