The potential role of magnetic resonance (MR) imaging in the diagnosis of breast disease has been investigated since the late 1970s. Conventional MR imaging has not been reliable for diagnosis of breast masses, and so contrast MRI using Gd-DTPA has been performed. In particular the gradient echo (GRE) technique combined with administration Gd-DTPA (i.e., dynamic MRI) improves detection and tissue characterization of breast masses. In recent studies, breast MR imaging has shown up to 100% sensitivity in the detection of breast cancer. On the other hand, its specificity varies between 37% and 98% because of the fact that may benign lesions are also enhanced with many contrast media, similar to breast cancer. To improve the specificity of MR imaging, MR-guiding localization and fine needle aspiration biopsy for breast masses will be necessary. Recently breast conserving therapy has been widely accepted in our country, so we deduce that MRI is useful method for detecting multifocal or multicentric breast cancer.