A novel three-dimensional (3D) electrical impedance mammography (EIM) system, named the combined EIM (CEIM) system, is introduced. It combines a ring electrode array with a planar electrode array that can operate independently or together. Three operational modes of the CEIM system are presented. Using a close-to-realistic digital breast phantom, the CEIM system is shown to provide enhanced detectability of a tumour deep within the tissue, as required for a largevolume breast. An implicit comparison with the authors’ former MK4 system demonstrates the benefits of this integrated multimode mammography system.