X-ray absorption spectroscopic studies have been systematically carried out at the Ir L(III)-edge for a series of perovskite compounds, A(2)BIrO(6) (A = Ba, Sr, and La; B = Zn, Mg, Y, Ca, Li, and Sr), in which the iridium ions with various oxidation states +IV (d(5)), + V (d(4)), and +VI (d(3)) are stabilized in an octahedral site of oxide lattices in order to obtain electronic and local structural information on the iridium upon the change of its oxidation state. On the basis of one-electron approximation and crystal field theory, XANES spectra for the present compounds clearly showed that the white line shapes and positions reflect the local site symmetry and oxidation state of the absorbing iridium atom well. The transition to e(g) states oriented directly to oxygen ligands in O-h symmetry is influenced more than that to t(2g) states by the change of oxidation state. A precise inspection of the white line positions indicated to us that the transition metal ion with a high oxidation state would be more preferable to induce a variety of physicochemical properties through the change in chemical environments. A good linear relationship is observed between the difference in peak areas for each transition state and the oxidation state of the iridium. It has been quantitatively studied how the A cation size and the ionicity of the B-O bond could influence the covalency of the Ir-O bond. By means of EXAFS analysis, the ionic radius of octahedrally coordinated Ir-VI could be determined to be 0.521 Angstrom from the average Ir-O bond distances for each oxidation state of the iridium and Shannon’s ionic radii of Ir-III, Ir-IV, and Ir-V ions. A linear relationship between the Debye-Waller factors and the Ir-O bond distances suggests that the IrO6 octahedron in the present compounds is nearly regular irrespective of the crystal symmetries. Effects of the oxidation state of the probed metal ions on the EXAFS analysis also have been examined.