  Strong magnetic field of accreting neutron stars ($10^{14}$ G) is hard to
probe by X-ray spectroscopy but can be indirectly inferred from
spin-up/spin-down measurement in X-ray pulsars. The existing observations of
slowly rotating X-ray pulsars are discussed. It is shown that magnetic fields
of neutron stars derived from these observations (or lower limits in some
cases) fall within the standard $10^{12}$-$10^{13}$ G range. Claims about the
evidence for accreting magnetars are critically discussed in the light of
recent progress in understanding of accretion onto slowly rotating neutron
stars in the subsonic regime.
