  An analysis of the sensitivity of supersymmetric dark matter to variations in
the b quark mass is given. Specifically we study the effects on the neutralino
relic abundance from supersymmetric loop corrections to the mass of the b
quark. It is known that these loop corrections can become significant for large
$\tan\beta$. The analysis is carried out in the framework of mSUGRA and we
focus on the region where the relic density constraints are satisfied by
resonant annihilation through the s-channel Higgs poles. We extend the analysis
to include CP phases taking into account the mixing of the CP-even and CP-odd
Higgs boson states which play an important role in determining the relic
density. Implications of the analysis for the neutralino relic density
consistent with the recent WMAP relic density constraints are discussed.
