Metformin is an oral antihyperglycemic agent used in the therapy of noninsulin-dependent diabetes mellitus and does not cause hypoglycemia at the therapeutic dose. Its mechanism of action may involve an increased binding of insulin to its receptors and glucose uptake at the post-receptor level. The purpose of the present study was to evaluate the bioequivalence of two metformin tablets, Glucophage (Daewoong Pharmaceutical Co., Ltd.) and Glycomin (Ilsung Pharmaceuticals Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The metformin release from the two metformin tablets in vitro was tested using KP VII Apparatus II method with various dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty four normal male volunteers, $23.75{pm}1.96$ years in age and $68.77{pm}10.41;kg$ in body weight, were divided into two groups with a randomized $2{ imes}2$ cross-over study. After one tablet containing 500 mg as metformin was orally administered, blood was taken at predetermined time intervals and the concentrations of metformin in serum were determined using HPLC with UV detector. Besides, the dissolution profiles of two metformin tablets were very similar at 떠1 dissolution media. The pharmacokinetic parameters such as $AVC_t,;C_{max};and;T_{max}$ were calculated. The ANOVA test was performed for the statistical analysis of the logarithmically transformed $AVC_t;and;C_{max}$, untransformed $T_{max}$. The results showed that the differences in $AVC_t,;C_{max};and;T_{max}$ between two tablets based on the Glucophage were 0.09%, 6.09% and -8.22%, respectively. There were no sequence effects between two tablets in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) $(e.g.,;log(0.94){sim}log(1.09);and ;log(1.01){sim}log(1.15)$;for;AVC_t;and;C_{max},;respectively)$, indicating that Glycomin tablet is bioequivalent to Glucophage tablet.