An attempt has been made to synthesize CdS-Ag2S core-shell and composite nanoparticles using AOT/n-heptane/water microemulsion technique. We have systematically studied the different microemulsion mixing methods to prepare core and shell nanoparticles. Four methods have been used. Whilst all methods produced nanoparticles and nanocomposites, only two, i.e. the post-core and partial microemulsion methods have shown promise for core and shell formation and enhanced stability and sphericity of the nanoparticles. These core and shell nanoparticles and nanocomposites have been characterized using TEM, EDAX, photoluminescence and UV-Vis spectrophotometer techniques. Results and possible mechanism of formation of nanoparticles via all four methods have been discussed.