The lithopone pigment nanoparticles were synthesized by the reverse microemulsion rout. The N,N-bis-(2-hydroxy ethyl) oleamide (NHEO) surfactant/n-hexanol/water microemulsion system was used to produce white precipitate. The product was characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy, transmission electron microscopy, simultaneous thermal analysis, laser light scattering, and chemical analysis. The effect of main factors on the reduction of product particles size evaluated by a 2 3 factor design. The average particle size for the product was found to be 5.4 nm. The results indicated that the nanopowder composed of 29.1% ZnS and 71.0% BaSO4 and was comparatively whiter than the commercial one.