A bioequivalence study of $Sudo^{TM}$ Ranitidine HCI tablet (Sudo Pharma. Ind. Co., Ltd.) to $Curan^{TM}$ tablet (Il Dong Pharma. Ind. Co., Ltd.) was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty four healthy male Korean volunteers received each medicine at the ranitidine hydrochloride dose of 150 mg in a 2x2 crossover study. There was a one week wash-out period between the doses. Plasma concentrations of ranitidine were monitored by a high-turbulent liquid chromatography (HTLC) for over a period of 12 hours after drug administration. $AUC_t$ (the area under the plasma concentration-time curve from time zero to 12 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found far all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for $Sudo^{TM}$ Ranitidine $HCl/Curan^{TM}$ were 0.92-1.00 and 0.90-1.03, respectively. These values were within the acceptable bioequivalence intervals of 0.80-1.25. Thus, our study demonstrated the bioequivalence of $Sudo^{TM}$ Ranitidine HCI and $Curan^{TM}$ with respect to the rate and extent of absorption.