The Breast Imaging Reporting and Data System (BI-RADS) is a practical tool developed by the American College of Radiology to standardize the description of mammography, ultrasound study, and magnetic resonance mammography. BI-RADS includes recommendations for the structure of a protocol to describe radiologic studies; terminology to characterize three major types of lesions (focus, mass, contrasting area); as well as assessment categories and their corresponding recommendations for further patient management. The publication gives general information on the new edition of BI-RADS (2013) and illustrates its use to interpret magnetic resonance mammograms in breast cancer. The wider introduction of BI-RADS at all stages from screening to diagnostic verification will improve the quality of diagnosis and prognosis in breast tumor diseases.