The objective of this study was the measurement of skin temperature of patients with decubitus ulcers during long-term illness. IC temperature sensors, arranged on the bed sheet, were used to monitor body movement without attaching sensors directly tot he skin; the spatial distribution of temperature was measured. The results of these studies showed that decubitus ulcers were caused by reduced body movement; higher temperature distribution was observed in the area of decubitus ulcers than in normal areas. The difference in skin temperature between the decubitus ulcer areas and normal areas varied from 1.6 °C. to 3.1 °C. The temperature in the decubitus ulcer area was found to be higher than the temperature of areas in which decubitus ulcers were either developing or healing.