Azelastine, a phthalazinone derivative, is an antiallergic agent which demonstrates histamine H₁-receptor antagonist activity and also inhibits histamine release from mast cells following antigen and non-antigen stimuli. Thus, azelastine may be useful in the management of both asthma and allergic disorders. The purpose of the present study was to evaluate the bioequivalence of two azelastine hydrochloride tablets, Azeptin^(TM) (Bu Kwang Pharmaceutical Co., Ltd.) and Azela^(TM) (Kyung Dong Pharmaceutical Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). Eighteen normal male volunteers, 22.44±2.01 years in age and 61.99±6.18 ㎏ in body weight, were divided into two groups and a randomized 2 × 2 cross-over study was employed. After two tablets containing 1 ㎎ of azelastine hydrochloride per tablet were orally administered, blood was taken at predetermined time intervals and the concentrations of azelastine in serum were determined using HPLC with fluorescence detector. Pharmacokinetic parameters such as AUC_t, C_(max) and T_(max) were calculated and ANOVA test was utilized for the statistical analysis of the parameters. The results showed that the differences in AUC_t, C_(max) and T_(max) between two tablets were -6.45%, -2.60% and -7.14%, respectively, when calculated against the Azeptin^(TM) tablet. The powers (1-β) for AUC_t and C_(max) were 96.65% and 88.47%, respectively. Minimum detectable differences (△) at α=0.05 and 1-β=0.8 were less than 20% (e.g., 14.40% and 17.65% for AUC_t and C_(max), respectively). The 90% confidence intervals were within ±20% (e.g., -14.87∼1.97 and -12.92∼7.72 for AUC_t and C_(max), respectively). Two parameters met the criteria of KFDA for bioequivalence, indicating that Azela^(TM) tablet is bioequivalent to Azeptin^(TM) tablet.