The purpose of the present study was to evaluate the bioequivalence of two alprazolam tablets, Xanax 0.25 mg (Pharmacia Korea Pharm. Co., Ltd.) and Zyren 0.25 mg (Kwang Dong Pharm. Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The alprazolam release from two alprazolam tablets in vitro was tested using KP VIII Apparatus II method with various dissolution media (pH 1.2, 4.0, 6.8 buffer solutions and water). The dissolution profiles of two alprazolam tablets were very similar at all dissolution media. Twenty four healthy male volunteers were divided into two groups with a randomized 2${ imes}$2 cross-over study. After four tablets (1 mg alprazolam) were orally administrated, blood was taken and the concentrations of alprazolam in serum were determined using LC/MS/MS. The pharmacokinetic parameters such as $AUC_t$, $C_max$ and $T_max$were determined. Our results showed that the differences in $AUC_t$, $C_max$ and $T_max$ between two alprazolam tablets based on the Xanax were -11.65%, -4.44% and -39.31%, respectively. There were no sequence effects between two tablets in these parameter. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25)(e.g., log(0.8386)${sim}$log(0.9453) and log(0.8596)${sim}$log(1.1040) for $AUC_t$, $C_max$, respectively). Thus, Zyren 0.25 mg tablet was bioequivalent to Xanax 0.25 mg tablet.