The aim of this investigation was to determine which positions resulted in the lowest pressures to the skin of persons lying in bed. Pressures were recorded in 10 different lying positions on 2 mattresses in 62 healthy volunteers. The study revealed that the 30 degrees semi-Fowler position and the prone position resulted in the lowest interface pressures. The 30 degrees laterally inclined position had lower pressure readings than the 90 degrees side lying position; 90 degrees side lying position gives the highest pressure readings and thus should be avoided. A Tempur polyethylene-urethane mattress reduces interface pressures by 20 to 30% in comparison to a standard hospital mattress (12-cm-thick cold foam).