This paper aims to investigate the effects of biocompatible polymers on the physicochemical and dissolution properties of poorly water-soluble drugs in nanoparticle systems. Four types of nanoparticles containing poorly water soluble fenofibrate were prepared using solvent evaporation technique with different biocompatible polymers such as polyvinylpyrrolidone (PVP), hydroxypropylmethyl cellulose(HPMC), carbopol and ethylcellulose. Their physicochemical properties were investigated using scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction. The solubility and dissolution of nanoparticle-entrapped fenofibrate were compared with those of free drug powder. Biocompatible polymers affected themorphology and sizes of fenofibrate nanoparticles. PVP or carbopol-based nanoparticles showed spherical appearance, whereas HPMC or ethylcellulose-based nanoparticles formed aggregates with irregular shape. The particle sizes increased in the order of the nanoparticle prepared with carbopol B PVP\HPMC\ethylcellulose. The size of PVP-based nanoparticles did not significantly differ from that of carbopol-based nanoparticles, showing the mean sizes of ca. 10 lm. As compared to free drug powder, the solubility and dissolution of the drug in nanoparticles increased in the order of PVP[HPMC[carbopol[ethylcellulose. The enhanced solubility and dissolution of poorly water-soluble fenofibrate via nanoparticle system did not depend on particle size but on crystallinity. In conclusion, in nanoparticle development of poorly water-soluble drugs such as fenofibrate, the nature of biocompatible polymers plays an important role in the physicochemical and dissolution of poorly water-soluble drugs in the nanoparticles.