The tungsten disulfide (WS2) nanoparticles (most probably inorganic fullerene (IF)) with a narrow size distribution were synthesized by a reverse micelle technique for the first time. The particle size was controlled by varying water-to-surfactant molar ratio (W-0), aging time and reagent concentration. The synthesized WS2 nanoparticles were characterized by zetasizer, UV-visible spectrophotometers and transmission electron microscopy (TEM). The WS2 nanoparticles with particle diameter size of 7-12 nm were obtained via 24 h aging time. The particle size was controlled by changing the aging time and molar ratio of water/surfactant. Doubling W-0 increased the amount and particle size of WS2 by 22 and 26%, respectively. The effect of aging time in the range of 6-24 h was investigated and the complete disappearance of yellowish color at 24 h resulted in an optically clear solution, which was the indication of WS2 formation with 100% conversion of reactant ((NH4)(2)WS4) in the batch reactor. (C) 2012 Elsevier Ltd. All rights reserved.