  We find general relativistic solutions of equilibrium magnetic field
configurations in magnetars, extending previous results of Colaiuda et al.
(2008). Our method is based on the solution of the relativistic Grad-Shafranov
equation, to which Maxwell's equations can be reduced in some limit. We obtain
equilibrium solutions with the toroidal magnetic field component confined into
a finite region inside the star, and the poloidal component extending to the
exterior. These so-called twisted-torus configurations have been found to be
the final outcome of dynamical simulations in the framework of Newtonian
gravity, and appear to be more stable than other configurations. The solutions
include higher order multipoles, which are coupled to the dominant dipolar
field. We use arguments of minimal energy to constrain the ratio of the
toroidal to the poloidal field.
