A new spectrophotometric determination of technetium has been developed by means of the solvent extraction of tris(1,10-phenanthroline)iron(II) ([Fe(phen)(3)(2+)]) with pertechnetate into nitrobenzene. The concentration of technetium can be determined by measuring the characteristic absorbance at 516 nm (epsilon = 11,700M(-1).cm(-1)) in the organic phase. An important feature of the proposed method is that the concentration of pertechnetate can be determined without complicated processes such as the reduction of pertechnetate and the subsequent formation of a colored chelate.