[en] Method for photometric determination of molybdenum in complex alloys on the iron basis having high content of molybdenum is suggested. Molybdenum is transformed to a water-soluble coloured complex by N-benzoyl-2-sodium-sulfonate-N-phenyl-hydroxylamine (BSSPHA) at a H⁺ ion concentration from 0.1 to 2.0 gxion/l. Effect of large ions (3) almos amounts is eliminated with adding 0.13-0.14 g muriatic hydroxylamine to the reaction mixture. Rectilinear dependence of optical density of solutions on the Mo concentration in the ranges from 100 to 2000 μg in 25 ml finite volume was observed under chosen conditions. Color of the Mo - BSSPHA complex is stable during several days. Fe(2) doesn't interfere with the determination in any quantities, V(5) interfers at a content over 500μg, Ti > 1000μg Duration of 10 sample analysis constitutes 78 hours. The method possesses high accuracy (+-0.1 relative error) and good reproductivity