ZnS and manganese doped ZnS (ZnS:Mn2+) nanocrystals were prepared by adding Na2S to the solutions of zinc oleate and zinc oleate mixed with Mn(NO3)(2). It was done by thermal decomposition using auto-clave method. The aging of the complexes in auto-clave resulted in AS and Mn2+ doped ZnS nanoparticles. The diameters of both nanoparticles were determined as approximately 10.3 +/- 2.1 nm from XRD line widths and TEM images. The ZnS:Mn2+ nanoparticles emitted at 500 nm similar to650 nm (lambda(max) = 575 nm) in contrast to ZnS nanoparticles. The luminescence Intensity of ZnS:Mn2+ highly depend on the amount of Mn2+ added.