Abstract: AIM: To compare efficacy of two designs and three test approaches in individual bioequivalence and estimate sample size.METHODS: Monte-Carlo simulation research was applied.RESULTS: Sample size under 2×4 cross-over design is less than that under 2×3 crossover design.When, estimation method is feasible in estimating sample size.Whereas is close to 0.2,we can use test method to determine sample size.Then, either method is chosen to determine sample size.Consequently, we are able to choose appropriate method to estimate sample size.CONCLUSION: Sample size of individual bioequivalence is different as σWR, σD and designs are changed.

Key words: individual bioequivalence, sample size, efficacy