  We present the full next-to-next-to-leading order (NNLO) corrections to the
coefficient function for the polarized cross section $d \Delta\sigma/d Q$ of
the Drell-Yan process. We study the effect of these corrections on the process
$p+p\to l^+l^-+`X'$ at an C.M. energy $\sqrt{S}=200 GeV$. All QCD partonic
subprocesses have been included provided the lepton pair is created by a
virtual photon, which is a valid approximation for a lepton pair invariant mass
$Q<50 GeV$. For this reaction the dominant subprocess is given by $q+\bar q\to
\gamma^*+`X'$ and its higher order corrections so that it provides us with an
excellent tool to measure the polarized sea-quark densities.
