Sarpogrelate HCl (SGL) has been used clinically as an anti-platelet drug for the prevention of thrombus, proliferation of vascular smooth muscle cells and platelet aggregation. This study was to investigate the bioavailability of sustained-release solid dispersion (SR-SD) formulation of SGL to sustain the drug release for up to 24 h. The SR-SD formulations with various drug-to-polymer ratios were prepared by hot-melt coating method. Waxy material carriers such as Compritol 888 ATO and stearyl alcohol were added to SGL and different amounts of HPMC K 15 (HPMC) were mixed. Dissolution profile and bioavailability were compared to SGL powder. Compritol 888 ATO showed the controlling effect of the initial release rate of drug from the formulation and the controlling effect was increased for 24 h by addition of HPMC. As the amount of HPMC increased, the drug release rate from SR-SD decreased because HPMC formed gel layer in aqueous media. Pharmacokinetic study showed that the AUC and Tmax of SGL in SR-SD formulation increased as compared to the SGL powder. These data suggest that the SR-SD formulation effectively controls the drug release rate for 24 h, hoping to be useful for the development of once-a-day formulation of SGL.