The 2009 NCCN Clinical Practice Guidelines in Oncology for Breast Cancer Screening and Diagnosis include significant updates for the role of MRI in screening women at increased risk for breast cancer. The NCCN now recommends considering breast MRI as an adjunct to annual mammography and clinical breast examination for women who have a BRCA1 or -2 mutation or who have a first-degree relative who has a BRCA1 or -2 mutation but who have not undergone genetic testing themselves; those who are determined to have a lifetime risk greater than 20% based on models that are highly dependent on family history; and those with a history of lobular carcinoma in situ. MRI is also recommended for patients who underwent radiation treatment to the chest between 10 and 30 years of age, and in those who carry or have a first-degree relative who carries a genetic mutation in the TP53 or PTEN genes (Li-Fraumeni, Cowden, and Bannahyan-Riley-Ruvalcaba syndromes). MRI is specifically not recommended for screening women at average risk for breast cancer. This article describes the peer-reviewed, published clinical research trials evaluating breast MRI in high-risk patients, on which the NCCN guidelines were based, and provides suggestions for future research.