We propose CuIn3Te5 as a ternary semiconductor material for narrow-bandgap thin-film solar cells. Well-developed CuIn3Te5 grains were obtained at a substrate temperature of 250 °C by single-step co-evaporation. The best solar cell that was fabricated using 4·0-µm-thick CuIn3Te5 layers grown at 250 °C yielded a total area efficiency of 6·92% (Voc = 407 mV, Jsc = 33·1 mA/cm2, and FF = 0·514). To clarify the loss in the device performance, the cell was compared with a standard CuInSe2 reference cell. A band diagram of the CdS/CuIn3Te5 solar cell was also presented. Copyright © 2011 John Wiley & Sons, Ltd.