Oriented AgI crystals have been electrodeposited onto tin doped indium oxide (ITO) glass through electrochemical generation of acid in aqueous solutions at room temperature. When the released hydrogen ions lower the pH at the surface of the ITO working electrode, silver ions are set free from the Ag-ethylenediaminetetraacetic acid disodium complex and then react with iodide ions to form AgI deposits. The electrodeposited AgI crystals are mixed with beta/gamma AgI phases. The composition of them was analyzed by Rietveld method, and the ratio of beta/gamma AgI phase was about 44/56. The orientation of the electrodeposited AgI crystals is dependent on the applied potentials. At a low applied potential, the obtained AgI crystals have a [002] preferred orientation with a rod shape for beta-AgI and a [111] preferred orientation with triangular shape for gamma-AgI. The absorption spectra of the electrodeposited AgI crystals were measured, and the electrodeposited AgI semiconductor had a direct bandgap of 2.85 eV. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3545059] All rights reserved.