Elements Mo(VI), W(VI) and V(V), polymerize at low pH (within the approximate pH range 2-6) to form polyanions Mo7O24-n (OH)(n)((6-n)-) (n=0, 1, 2, 3), W12O41-2n(10-4n)- (n=0, 1) and V10O28-n(OH)(n)((6-n)-)(n=0, 1, 2). Extraction of these complex species leads to the high ratio of the concentration of metal and amine in the organic phase. Quantitative information on the possibility of extracting V(V), Mo(VI), and W(VI) from sulphate solutions by primary amine Primene JMT with respect to initial concentration of metals and sulphuric acid are presented. Experimental results confirmed the advantage of Mo, W and V extraction by primary amine from sulphuric acid solutions mainly within the range of pH in which the polymeric anionic complexes are present. It was found that several equilibrium reactions must be taken into account. The reaction of amine salts forming, anion exchange reactions and in case of sulphate groups absence probably addition reactions take place. Primary amine Primene JMT contrary to tertiary amines enables effective extraction also from weak acidic solutions. It was concluded that the behaviour of all the three elements studied is very similar.