Monodispersed AgIn5S8 microspheres were synthesized using a one-pot solution method and characterized with X-ray diffraction, UV-vis diffuse reflectance spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy and N-2 adsorption-desorption isotherm. The results indicated that the AgIn5S8 microspheres were of cubic spinel structure and the mean diameter of about 0.5 mu m. In addition, the visible light photocatalytic activity of AgIn5S8 microspheres was also investigated at room temperature. The AgIn5S8 microspheres showed very high photocatalytic activity for the degradation of methyl orange with a degradation efficiency of about 98% under visible light irradiation for 20 min. (c) 2012 Elsevier Ltd. All rights reserved.