In the present study, we report the synthesis of CdS nanoparticles using a liquid-liquid interface reaction technique. CdS nanoparticles and disk-like aggregates of CdS nano-particles were obtained at the oil/water interface. The disk-like aggregates of CdS nano-particles were characterized by transmission electron microscopy and electron diffraction. Energy-dispersive spectroscopy was employed to confirm the components of the disk-like aggregates of CdS nano-particles.