Sorption characteristics of modified poly(ethyleneimine) supports which contain ammonium, carboxymethyl or phosphonomethyl groups have been determined for uptake of molybdenum(VI), rhenium(VII) and vanadium(V). Results suggest the separation of rhenium(VII) toward molybdenum(VI) from loaded N-carboxymethyl derivative by selective elution with 1M sulfuric or perchloric acid. Moreover, vanadium(V) should be also selectively eluted from molybdenum(VI), iron(II) or iron(III).