AgInSe2 ternary semiconductor thin films are deposited on glass substrates and indium-doped-tin-oxide (ITO)-coated glass substrates using the selenization of magnetron sputtered Ag-In metal precursors. X-ray diffraction (XRD) and energy-dispersive analysis of X-ray (EDAX) results show that the crystal phase of samples changed from AgInSe2 to a solid mixture of AgInSe2 and Ag2Se with a decrease in the [In]/[In + Ag] molar ratio in samples. The direct and indirect energy band gaps of the samples vary in the ranges of 1.27-1.45 eV and 0.91-1.17 eV, respectively, depending on the [In]/[In + Ag] molar ratio in samples. The flat-band potentials of samples are in the range of -0.47 to -0.71 V (vs. normal hydrogen electrode) in a solution containing Na2S (0.35 M) + K2SO3 (0.25 M) obtained using Mott-Schottky measurements. The maximum photocurrent density of the samples on ITO-coated glass substrates is 31.7 mA/cm(2) at an external potential of +1.0 V (vs. Ag/AgCl) in the solution containing Na2S (0.35 M) + K2SO3 (0.25 M) ions. Crown Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.