Bioequivalence test of commercially available rifampicin capsules was performed. Sixteen volunteers were divided into 2 groups and the reference and test drug were given orally (450 mg) by cross-over design. Statistical evaluation of AUC, $C_{max};and;T_{max}$ involved an analysis of variance (ANOVA). The differences of mean value in AUC, $C_{max};and;T_{max}$ between the reference and test drug were within 20% with reference drug. ANOVA showed no significant differences for ‘between group’, ‘drug’ and ‘period’, but not for ‘between subjects’. The power of test $(1-{eta});of;AUC;and;$C_{max}$ was larger than 0.8 and the confidence of bioavailability was $within;{pm}20%$. From these results, it was concluded that the two preparations were bioequivalent for AUC and $C_{max}$, but was not for $T_{max}$.