The bioequivalence of two nicotine patches was evaluated in 16 normal male volunteers (age 21 ~ 27 yrs) following single transdermal application. Test product was "Nicostop patch" made by Sam Yang Co. and reference product was "Nicotinell TTS patch" made by Korean Searle Ciba-Geigy Co. After nicotine patches were applied onto the inside of the forearm, blood was taken at predetermined time intervals and the nicotine concentration in plasma was determined with a sensitive GC method using NPD detector. AUC and Cmulcorner were calculated and statistically analyzed for the bioequivalence of the two products. The results showed that the differences in AUC and $C_{msx}$between two products were 5.47% and 2.70%, respectively. The powers (1-$eta$) for AUC and $C_{max}$. were >90% and 88.76%, respectively. Detectable differences($Delta$) and confidence intervals were all less than 20%. All of these parameters met the criteria of KFDA for bioequivalence, indicating that "Nicostop patch" is bioequivalent to "Nicotinell TTS patch" . . .