  We present a QCD analysis of the strange and charm contributions to the
neutrino deep inelastic structure function $xF_3$. We show that next-to-leading
order effects, which are relatively important for $F_2$, play a lesser role in
the case of $xF_3$. The neutrino--antineutrino difference $xF_3^{\nu} -
xF_3^{\bar \nu}$ provides a new determination of the strange density, which
exhibits some advantages with respect to other traditional methods.
