The purpose of this study was for the enhancement of dissolution rate of ketoprofen. The solid dispersions composed of ketoprofen(KP) and polyethylene glycol(PEG) 4000 or 6000 were prepared by fusion method at various ratios of KP to PEG (0.5 : 10, 1 : 10, 2 : 10, 3 : 10 and 4 : 10(w/w)) and their physical mixtures were also prepared at the above ratios. Dissolution tests, X-ray diffraction study and differential scanning calorimetry study were carried out. It was found that the dissolution rates of solid dispersion and physical mixture at any ratio of the two components discribed above were greater than that of the pure ketoprofen. X-ray diffraction studies of ketoprofen suggested that less than 1 to 10 ratio of ketoprofen to PEG4000 (or 6000) was required to dispersion amorphous state in the carrier. In addition, the studies of DSC showed that ketoprofen had a sharp endothermic peak at $94^{circ}C$ but not for the solid dispersion at the same temperature.