Organic-inorganic hybrid light emitting diodes (LEDs) were fabricated by incorporating cadmium sulphide (CdS) nanoparticles in hole transporting layer and light emitting materials of a polymer LED. The CdS nanoparticles with size of 10 nm were synthesized by precipitation technique. The LEDs incorporated with the CdS nanoparticles show a reduction in turn on voltage and luminance. When the nanoparticles are incorporated in a suitable fluorene based light emitting polymer, the luminance is increased along with the decrease of turn on voltage.