A thioglycolic acid (TGA)-assisted hydrothermal process has been developed to synthesize cadmium sulfide nanostructures via reaction between a new precursor cadmium (II) phthalate and TGA. X-ray diffraction, transmission electron microscopy, photoluminescence spectroscopy and Fourier transform infrared were employed to characterize the obtained product. The effects of the reactant concentration, mole ratio of TGA to the Cd2+, temperature and reaction time on the morphology, size of particles, and phase of nanocrystalline CdS products were investigated.