Described herein is a method and system for shimming an MRI magnetic field generating assembly, wherein a plurality of shims are secured relative to a surface of the magnetic field generating assembly to at least partially correct inhomogeneities in the magnetic field generated by the magnetic field generating assembly. In one aspect, the shims are arranged along a plurality of concentric geometric shapes each having at least five sides. In an alternative aspect, the shims are arranged in a plurality of rows and columns, where the rows are normal to the columns. In another aspect, at least one of the shims is a flat plate of magnetic material including a top edge, a bottom edge, side edges, and face surfaces. The bottom edge is the proximal portion of the flat plate relative to the magnetic field generating assembly, the top edge is the distal portion of the flat plate relative to the magnetic field generating assembly, and the face surfaces are aligned with a direction of the magnetic field generated by the magnetic field generating assembly.