  We investigate the effect of heavy flavor contributions to vector boson ($V$
= $\gamma$, $Z$, $W$) production which is described by the Drell-Yan mechanism.
All reactions with bottom and top quarks ($Q_i$ = $b$, $t$) in the final state,
like $q_1 + \bar{q}_2\rightarrow V + Q_1 + \bar{Q}_2$ and $g + g\rightarrow V +
Q_1 + \bar{Q}_2$, are considered. This study also includes the virtual
contributions containing heavy flavor loops which were not taken into account
earlier in the literature. Our analysis reveals that the above corrections to
the Drell-Yan cross section are very small. Only at energies characteristic for
the LHC they are of the same order of magnitude as the order \alphastwo~QCD
contributions due to light quark and gluon subprocesses calculated earlier in
the literature.
