Quantum dots (QDs) are semiconductor nanoparticles with very interesting optical properties, like high quantum yield or narrow and size-tunable fluorescence spectra. Current applications of QDs are wide-spread, their use as fluorescence labels in bioassays being one of the most promising applications. CdSe semiconductor nanoparticles (NPs) have been prepared by the organometallic pyrolysis method developed by Murray et al , and modified by Peng et al. Formations of the quantum dots nanoparticles were clearly seen in the TEM pictures. Powder X-ray diffraction (XRD) confirmed the structure of the products. In addition, the crystalline phase and size distribution of the nanocrystals are determined by XRD and TEM, respectively .The optical properties were assessed by UV-Vis measurements.