The evolution of the magnetic field in an accreting neutron star is investigated using a fully general relativistic treatment and assuming that initially the currents supporting the field are completely confined to the crust. We find that the field decay slows down owing to the inclusion of the curvature of space–time but the final results do not differ significantly from those obtained assuming a flat space–time. We also find that such modifications are small compared with the uncertainties introduced by a lack of precise knowledge of the neutron star microphysics.