Transcutaneous oxygen tension (TCPO2) is a recognized techniques for evaluating support surfaces as a pressure ulcer prevention method. Transcutaneous oxygen tension was measured over the sacral area of 20 volunteers positioned on five different mattresses, including a standard mattress. No specific change was noted on resting values (M = 68.2 mm Hg, SD = 9.4) before each of the five protocols were begun. Mean values were 17.9 mm Hg (SD = 27.9) for a nonspecific hospital mattress, 30.15 mm Hg (SD = 29.5) for the first foam mattress, 30.25 mm Hg (SD = 28.5) for the second foam mattress, 50.5 mm Hg (SD = 23.1) for the air mattress, and 50.95 mm Hg (SD = 21.6) for the water-filled mattress. Results showed statistical differences between the standard mattress and the four mattresses tested and between the foam mattresses and the two other mattresses. There was an inverse correlation between skinfold thickness and a decreased TCPO2 in contact area. Skinfold thickness could be an indicator of pressure ulcer risk. Further studies are needed to confirm the interest of this parameter.