Nanostructured Ag2S/CdS were synthesized by a two-step precipitation method, and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-Vis absorption spectra. With Ag2S highly dispersed in the CdS nanostructures, the photoactivity was evaluated by hydrogen evolution from aqueous solution containing Na2S/Na(2)So(3) as a hole scavenger under simulated solar light (AM1.5). When the concentration of Ag2S was 5% by weight, Ag2S/CdS showed the highest photocatalytic activity for hydrogen evolution, with the solar-hydrogen energy conversion efficiency approximately 0.7%. We investigated the effect of highly dispersed Ag2S on the photoactivity. Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu.