OBJECTIVE: To compare the skin temperature change between supine and prone position during application of hot pack on the back. METHOD: 15 healthy adults were recruited as subjects. We applied two hot packs to the lumbar region for two consecutive days. On the first day, the body part was on the top of hot pack and on the second day, the hot pack was placed over the body part. We measured peak skin temperature, skin temperature elevation, time required to peak skin temperature, skin temperature after 20 minutes and visual analogue scale(VAS) of subjective feeling of heat (hot). RESULTS: In the peak skin temperature, the means were 44.4+/-0.70degrees C and 42.7+/-0.99degrees C in the supine and prone position, respectively. In the skin temperature elevation, the means were 11.2+/-1.1degrees C and 9.5+/-1.6degrees C, respectively. In the time required to peak skin temperature elevation, the means were 6'49"+/-15" and 10'33"+/-15", respectively. In the skin temperature after 20 minutes, the means were 42.4+/-0.7degrees C and 41.6+/-0.8degrees C, respectively. In the VAS of subjective feeling of heat (hot), the means were 8.66+/-1.11 and 5.72+/-1.48, respectively. CONCLUSION: The patient's position is one of the important factors in determining temperature elevation. Therefore, it should be considered during application of the hot pack.