  We study the final state interaction effects in $B\to KK$ decays. We find
that the $t$ channel one-particle-exchange diagrams cannot enhance the
branching ratios of $\bar{B^0}\to K^0\bar{K^0}$ and $B^-\to K^0K^-$ very
sizably. For the pure annihilation process $\bar{B^0}\to K^+K^-$, the obtained
branching ratio by final state interaction is at ${\cal{O}}(10^{-8})$.
