© 2013, Hacettepe University, Faculty of Pharmacy. All rights reserved.In this study, paclitaxel loaded PLGA nanoparticles were prepared using emulsification-solvent diffusion method and the influences of polymer and emulsifier concentrations on particle size, zeta potential, encapsulation efficiency and in vitro release rate of the paclitaxel loaded PLGA nanoparticles were evaluated. It was observed that average particle size of the prepared nanoparticles were between 190 and 235 nm. The encapsulation efficiency of paclitaxel into the nanoparticles was between 53-89% and the release profiles of the nanoparticles exhibited an initial burst effect followed by a controlled release for 7 days. In vitro cytotoxicity studies showed that drug loaded nanoparticle formulation was more cytotoxic than the blank nanoparticle formulation. According to the results of the studies performed, it can be concluded that prepared nanoparticle formulations may be a considerable approach for paclitaxel delivery.