The aim of this study was to evaluate the pharmacokinetic parameters of two risedronate preparations. The clinical assessment was conducted on 46 healthy volunteers who received one tablet (Risedronate sodium 35 mg/tablet) in the fasting state, in a randomized balanced $2{ imes}2$ cross-over study design. After dosing of one tablet containing 35 mg risedronate sodium, blood samples were collected serially for a period of 48 hours. Plasma was analyzed for risedronate 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 48 hr) was calculated through the trapezoidal rule. $C_{max}$ (maximum plasma drug concentration) were compiled from the plasma risedronate concentration-time data of each volunteer. No significant sequence effect was found for the pharmacokinetic 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 0.8752 to log 1.1888 and log 0.8457 to log 1.1478, respectively. These values were within the acceptable intervals between 0.80 and 1.25. Therefore, this study demonstrated that no statistically significant difference was identified with respect to the rate and extent of absorption.