The study was performed to compare the dissolution, diffusion and absorption characteristics using Sartorius dissolution and absorption simulator and in vivo bioavailability of commercially available rifampicin capsules. Both brands C and F showed similar dissolution patterns and absorption properties through artificial gastric barrier in Sartorius simulator. Diffusion rate constants through the membrane of brands C and F were 3.04×40^(-3) and 2.88×10^(-3)㎝/min, respectively. Rifampicin capsules were administered orally to six fasted healthy volunteers according to cross-over design. The pharmacokinetic parameters between brands C and F, maximum plasma drug concentration (C_(max)), the time to reach C_(max), absorption rate constant and area under the curve (AUC_(0-24hr)), elimination rate constant, and amount of drug excreted in urine were 6.11 and 7.27 ㎍/㎖, 2.71 and 1.52 hr, 0.6371 and 1.6456 hr^(-1), 57.84 and 57.28㎍·hr/㎖, 0.1891 and 0.1734 hr^(-1), 119.98 and 119.93 ㎎, respectively. On the basis of experimental results, it was concluded that the bioavailability of brand C rifampicin capsules was almost the same as that of brand F rifampicin capsules.