In this work, we report a facile two-phase approach to synthesize nearly monodisperse cubic zinc sulfide nanocrystals. Toluene and water were used as separate solvents for zinc stearate and sodium sulfide, respectively, and oleic acid was used as a stabilizing ligand for the nanocrystals. Their photophysical properties were investigated by UV-vis absorption spectra. Transmission electron microscopy and selected area electron diffraction in combination with X-ray powder diffraction indicated the presence of pure cubic ZnS nanocrystals in good crystallization with the size ranged from about 2.0 to 5.0 nm in diameters. The possible mechanism was also presented. (C) 2008 Elsevier B.V. All rights reserved.