  We study the $K^*$ meson dissociation in heavy ion collisions during the
hadron gas phase. We use the production and absorption cross sections of the
$K^*$ and $K$ mesons in a hadron gas, which were calculated in a previous work.
We compute the time evolution of the $K^*$ abundance and the $K^* /K$ ratio
during the hadron gas phase. Assuming a Bjorken type cooling and using an
empirical relation between the freeze-out temperature and the central
multiplicity density, we are able to write $K^* /K$ as a function of ($ dN /d
\eta (\eta =0)$). The obtained function is in very good agreement with recent
experimental data.
