  The energy and zenith angle distribution of neutrino induced, upward going
muons can give direct information on the presence of $\nu$--oscillations in
precisely the range of parameters suggested as a solution of the atmospheric
neutrino problem. We discuss here the uncertainties in the theoretical
prediction. The shape of the zenith angle distribution of the muon flux is
quite insensitive to modifications of the theoretical input and is a good probe
for the existence of neutrino oscillations. We conclude that the existing data
sample on $\nu$--induced muons has the statistical power to confirm or refute
the $\nu$--oscillation solution of the atmospheric neutrino problem.
