[en] The two-valence state Bi³⁺ and Bi⁵⁺ of Bi in the semiconductor BaBiO₃ and in the BaPbsub(1-x)Bisub(x)O₃ (x = 0,0.25, 0.6 and 1) system has been determined from the EXAFS spectra above the Lsub(III)-edges of Ba, Pb and Bi. Peaks in the radial distribution function up to 5 A from the absorber have been identified through a model calculation using theoretical amplitudes and phase shifts and the interatomic distances from neutron diffraction measurements. Indication of local disorder in the Pb-Bi sub-lattice for the mixed compound was found. (author)