Magnetic field control over the optical switching is demonstrated for a nonlinear all-garnet magnetophotonic crystal with a microcavity (MC) layer possessing both third-order Kerr nonlinearity and magnetooptical activity. A significant enhancement of the effective refractive index of the microcavity layer is observed, that results in the light-induced spectral shift of the MC mode of 2 nm. It is shown that application of the external magnetic field leads to an increase of switching contrast by a factor of two. Possible mechanisms of photorefractive effect involved in the optical switching in all-garnet magnetophotonic crystals are discussed. (C) 2011 Elsevier B.V. All rights reserved.