  We report a preliminary measurement of the branching fraction for the decay
$B^0 \to K^0_sK^0_sK^0_s ,$ where the $K^0_s$ mesons are reconstructed through
the decay $K^0_s\to\pi^+ \pi^- .$ The measurement was performed on a sample of
$211\times 10^6$ $B\bar{B}$ pairs collected by the BABAR detector running on
the $\Upsilon (4S)$ resonance at the PEP-II storage ring. The branching
fraction is measured to be $${\cal B}(B^0 \to K^0_sK^0_sK^0_s)= (6.5\pm 0.8\pm
0.8) \times 10^{-6},$$ where the errors are statistical and systematic,
respectively.
