  We comment on the paper by Tanusri Ghosh and Somenath Chakrabarty, Phys. Rev.
D63, 043006 (2001). In that paper it was argued that a first-order transition
to quark matter in the core of a magnetar is absolutely forbidden if its
magnetic field strength exceeds $10^{15}$ G. However, we show in this comment
that if the quark anomalous magnetic moment and the population of higher Landau
levels is taken into account, it may still be possible for a first-order phase
transition from nuclear matter to quark matter to occur in the core of a
magnetar. These effects may also obscure the question of whether beta
equilibrium favors strange quark matter in the core of a magnetar.
