Breast MR imaging and PET allow physiopathological tissular approach of breast tumors. Breast MR imaging evaluates tumoral angiogenesis whereas PET analyzes metabolism of tumoral cells. Since 1985, breast MR imaging has been extensively studied. All these series agreed in the high sensitivity of breast MR imaging for detecting invasive breast cancers whereas the sensitivity varies from 60 to 85% in detecting ductal carcinoma in situ. However, its reported specificity varies between 60 and 97%, mainly due to some entities such as fibroadenomas and fibrocystic disease. Clinical indications are the diagnosis of local recurrences, the evaluation of pre-operative chemotherapy and breast prosthesis. PET of the breast is currently in clinical research phase. Early results are promising especially in the evaluation of pre-operative chemotherapy and diagnosis of isolated axillary nodes.