The complexation of ferron(7-iodo-8-hydroxy quinoline-5-sulphonic acid) with some metal ions of biological interest, such as Ag(I), Cu(II), Zr(IV), U(VI), Au(III), Ni(II), Zn(II), Mn(II), Fe(II), Fe(III), and Cr(III), has been studied potentiometrically using the Calvin-Bjerrum titration technique as employed by Irving and Rossotti. The protonation constant of the ligand and the stability constants of the respective metal complexes have been determined at constant temperature (25°C) and ionic strength (0.1M KNO3). Complexes of ferron with some metal ions have also been prepared and analyzed by ir. spectral data.