It is obvious that the examination of nerve conduction as a diagnostic tool is a relatively new field of interest with a state of still undergoing evaluation and improvement. Problems of technique and interpretation notwithstanding, determination of nerve conduction has progressed to a level where it is now used routinely as a part of the electrodiagnostic examination. The present study has been undertaken to determine the normal range of the motor nerve conduction velocity, distal motor latency, amplitude of the muscle action potentials, sensory nerve conduction velocity, distal sensory latency, amplitude and duration of the sensory nerve action potentials of median and ulnar nerves in healthy Korean. One hundred twenty healthy subjects (sixty male and sixty female) were examined. Their ages ranged from 5 to 69 in years and the subjects were arranged in three age groups of 5–9 years, 10–49 years and 50–69 years. The results obtained were as follows: l. In median nerve, mean values for motor nerve conduction velocity, distal motor latency, and amplitude of the muscle action potantials were 56.57± 4.55 (45.2–69.4) m/sec, 3.02±0.48 (1.6–4.5) msec, and 14.2±5.0 (4–28) mV, respectively. 2. In ulnar nerve, mean values for motor nerve conduction velocity, distal motor latency, and amplitude of the muscle action potentials were 58.60±5.06 (43.5–71.4) m/sec, 2.35±0.50 (1.3–4.1) msec, and 11.7±3.7(4–22) mV, respectively. 3. In median nerve, mean values for sensory nerve conduction velocity, distal sensory latency, amplitude and duration of the sensory nerve action potentials were 63.50±5.63 (53.1–75.9) m/sec, 2.37±0.38 (1.0–3.4) msec, 45.5±16.9 (13–120)u V, and 1.68±0.29 (0.9–2.5) msec, respectively. 4. In ulner nerve, mean values for sensory nerve conduction velocity, distal sensory latency, amplitude and duration of the sensory nerve action potentials were 65.34±5.16 (50.6–78.1) m/sec, 2.09±0.38 (1.3–3.2) msec, 45.6±17.5 (12–118) uV, and 1.54±0.32 (0.8–2.5) msec, respectively. In comparison of the obtained values of two nerves. 5. A significant difference was observed between motor nerve conduction studies of the median and ulnar nerves. 6. A significant difference was observed between sensory nerve conduction studies of the median and ulnar nerves except amplitude of the sensory nerve action potentials. 7. Nerve conduction velocity was significantly faster in sensory nerve than in motor nerve. In comparison of conduction velocities among 3 age groups. 8. Motor nerve conduction velocity of the median and ulnar nerves was slow in age groups of 5–9 years and 50–69 years as compared with that of age group of 10–49 years. 9. Sensory nerve conduction velocity of median nerve was slow in age groups of 5–9 years and 50–69 years as compared with that of age group of 10–49 years, and sensory nerve conduction velocity of ulnar nerve was slow in age group of 50–69 years as compared with that of age groups of 5–9 years and 10–49 years.