The role of skin temperature is very important in clinical neurophysiology but has often been neglected. In nerve conduction studies, lower normal temperature affects slower conduction velocities and increased nerve (sensory or mixed) action potential amplitudes. To determine the normal skin temperature in various parts of upper and lower extremities within close approximation of the nerve passages, the temperature was measured using Physitemp Model BAT-12 (Accuracy 0.1oC, Clifton, New Jersey, U.S.A.). Fifty-three neurophysiologically healthy adults (Age range, 22-77 years old) were tested : upper extremity, 20 (male, 7 ; female, 13) ; lower extremity, 33 (male, 11 ; female, 22). The total points of skin temperature measurement were 21 : upper extremity, 10 ; lower extremity, 11. The skin temperature for the upper and lower extremities was 34.6+/-0.9 degrees C (range, 32.6-36.7degrees C) and 33.4+/-1.1degrees C (range, 28.1-35.7degrees C), respectively. Although it is frequently time consuming, monitoring normal skin temperature will result in greater electrodiagnostic accuracy.