Effects of molybdenum on lead-induced neurotoxicity were investigated in sciatic nerve isolated from rat. The mechanism on toxicity reduction was examined by investigating tissue accumulation of lead, changes of nerve conduction velocity and concentrations of metabolites related to function of sciatic nerve in rats treated with 10 ppm-lead, 1mg/kg-molybdenum and both, respectively. In lead-intoxicated rat, the conduction velocity, myo-inositol concentration and Na'/K'ATPase activity of sciatic nerve were decreased by about 30%, 45% and 56%, respectively. However, molybdenum treatment significantly normalized the conduction velocity, Na'/K'ATPase activity and myo-inositol concentration of sciatic nerve in lead-intoxicated rat. Also, molybdenum treatment decreased the contents of lead in blood and sciatic nerve through promotion of urinary excretion of lead. These results suggest that molybdenum prevented neuropathy not only by reducing lead contents in sciatic nerve and blood, but also by enhancing Na'/K'ATPase activity in sciatic nerve.