The aim of this study was to evaluate the bioequivalence of two domperidone preparations. Bioequivalence assessment was conducted on 34 healthy volunteers who received two tablets (Domperidone Maleate, 12.72 mg/tablet) in the fasting state, in a randomized balanced $2{ imes}2$ cross-over study design. This whole study was performed according to the implementation guidelines of the Korea Food Drug Administration. After dosing of two tablets, blood samples were collected serially for a period of 36 hours. Plasma was analyzed for domperidone by using LC/MS/MS assay method. The analysis system was validated in specificity, accuracy, precision, and linearity. $AUC_t$, (the area under the plasma concentration-time curve from the zero-time to 36 hr) was calculated through the trapezoidal rule. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma domperidone concentration-time data of each volunteer. No significant sequence effect was found for the bioavailability parameters indicating that the cross-over design was properly performed. The 90%-Confidence intervals of the $AUC_t$ ratio and the $C_{max}$ were from log 0.8007 to log 1.1240 and log 0.8645- log 1.2483, respectively. These values were within the acceptable bioequivalence intervals between 0.80 and 1.25. Therefore, this study demonstrated that two formulations have bioequivalence with respect to the rate and extent of absorption.