A new reagent,N-o-tolyl-o-methoxybenzohydroxamic acid (OTMBHA) is proposed for highly sensitive and selective determination of Mo(VI) by rapid extraction of its yellow complex with isoamyl alcohol and simultaneous Spectrophotometric determination at 350 run. The complex follows Beer's law at this wavelength over the concentration range 0.5 to 10.5 μg/ml, the sensitivity being 0.010 μg of Mo/cm2(ε = 9.1 × 103). A 0.01Mreagent solution in isoamyl alcohol is adequate for complete extraction of molybdenum within 5 min. The method is found to be applicable to separation of molybdenum from many metals which constitute the nuclear fuels and fission products. Molybdenum was determined in steels.