To develop and aceclofenac soft capsule, four preparations with various solubilizers were prepared and their dissolution test was carried out. Among four preparations tested, a preparation with ethanolamine was selected a formula of aceclofenac soft capsule (Clanza S^(™), since it showed the fastest dissolution rate. Bioequivalence of aceclofenac tablet, Airtal^(™)(Dae-Woong Pharmaceutical Co., Ltd.) and aceclofenac soft capsule, Clanza S^(™)(Korea United Pharmaceutical Co., Ltd.) was evaluated according to the guideline of KFDA. Fourteen normal male volunteers (age 20-25 years old) were divided into two groups and a randomized 2×2 cross-over study was employed. After oral administration of one tablet or capsule containing 100 ㎎ of aceclofenac, blood ws taken at predetermined time intervals and the concentration of aceclofenac in plasma wa determined with an HPLC method under UV detector. The pharmacokinetic parameters (C_(max), T_(max) and AUC_(t)) were calculated and ANOVA was utilized for the statistical analysis of parameters using logarithmically transformed AUC_(t), C_(max) and T_(max) between Airtal tablet and Clanza soft capsule were 2.89%, 0.18% and 43.0%, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.250(e.g.log(0.81) - log(1.23) and log(0.89) - log(1.14)) for AUC_(t) and C_(max), respectively. Thus, the criteria of the KDFA guidelines for the equivalence was satisfied, indicating that Clanza S^(™) soft capsule is bioequivalent to Airtal^(™) tablet.