Nanoparticles based on polymeric compounds provide enhanced solubility of Doxorubicin in the aqueous solution. Various parameters like presence of organic solvent, surfactant concentration, loading efficiency, doxorubicin concentration affect the size of doxorubicin-polymeric nanoparticle. Under controlled conditions, doxorubicin loaded in situ on to the polymer like polyhydroxy butyric acid with particle size ranging between 10nm to 100nm was achieved by nanoprecipitation method. These nanoparticles were characterized under Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) to find the surface topology, particle size, drug loaded inside the polymer, structure of DOXPHB nanoparticles. The doxorubicin loaded PHB nanoparticle was observed for in vitro drug release study in a buffer solution mainly phosphate buffer solution for 5- 7 days. This reveals that the PHB polymer acts as an efficient carrier vehicle for the anticancer agents.