  The OPERA experiment at the CNGS beam has observed muon to tau neutrino
oscillations in the atmospheric sector. Based on this result new limits on the
mixing parameters of a massive sterile neutrino may be set. Preliminary results
of the analysis done in the 3+1 neutrino framework are here presented. An
update of the search for sterile neutrinos in the $\nu_{\mu} \rightarrow \nu_e$
channel is also given. The status of the searches for sterile neutrinos
performed at other Long--Baseline experiments (MINOS at NuMI beam and SuperK
with the atmospheric flux) is also briefly recalled. Finally, some personal
perspectives are discussed.
