  We study the robustness under perturbations of mixing times, by studying
mixing times of random walks in percolation clusters inside boxes in $\Z^d$. We
show that for $d \geq 2$ and $p > p_c(\Z^d)$, the mixing time of simple random
walk on the largest cluster inside $\{-n,...,n\}^d$ is $\Theta(n^2)$ - thus the
mixing time is robust up to constant factor.
