The growth of Cu2O crystallites electrodeposited in a nitrate bath with sodium dodecyl sulfate (SDS) under superimposition of a high magnetic field up to 12 T was investigated. Scanning electron micrographs show that the morphology of the crystallite changes from a starlike shape to a well-faceted octahedron with magnetohydrodynamic (MHD) convection. The magnetic field modifies the branching growth of Cu2O microcrystals.