[en] A method of simultaneous Mo and W determination by means of fluorescence radiation registration for their extraction control from ores has been developed. A two-channel system was applied for the detection. The Mo fluorescence radiation flux was registered on the first channel and W flux-on the second one. The measurement results depended considerably on the chemical content of the bulking agent, and especially, on Fe₂O₃ and MnO₂ quantities. γ-radiation of ¹⁰⁹Cd (E=22.2KeV) ensured the best contrast of measurements at W determination according to α-series (E=12KeV), and Mo according to K-series (E==17 KeV), For consideration of medium absorption properties a facility, used for absorption mass coefficient determination, is adapted to the tow-channel analyser. A relative mean-square deviation with chemical analysis comprised 2.8% in relation to tungsten and 4.3% J in relation to molybdenum. The analysis time is 7-8 min