  Situation with highly magnetized neutron stars in binary systems is not yet
certain. On the one hand, all best studied magnetars seem to be isolated
objects. On the other, there are many claims based on model-dependent analysis
of spin properties or/and luminosity of neutron stars in X-ray binaries in
favour of large fields. In addition, there are a few results suggesting a
magnetar-like activity of neutron stars in close binary systems. Most of
theoretical considerations do not favour even existence, not speaking about
active decay, of magnetar-scale fields in neutron stars older than
$\sim10^6$~yrs. However, alternative scenarios of the field evolution exist. I
provide a brief review of theoretical and observational results related to the
presence of neutron stars with large magnetic field in binaries and discuss
perspectives of future studies.
