This paper presents the use of multigrid (MG) technique to enhance the solution process of the FDFD method, hence speeding up the computational process of the iterative multi-region (IMR) algorithm. Furthermore, to achieve a high-performance computing, the presented IMR-MG technique becomes more efficient on a parallel platform, through the usage of multiprocessing, where each sub-region is solved on a separate processor. An example of the scattering from 2 two-dimensional objects using the IMR algorithm with multigrid technique in conjunction with parallel processing is presented to show the capabilities of the presented procedure to analyze large scattering problems with reasonable computer resources