Labetalol and MRI as initial medical and diagnostic modalities in a marfanoid patient with expanding ascending aortic aneurysm. Marfan syndrome is a hereditable disorder of connective tissue that causes several distinct cardiovascular abnormalities, including aortic regurgitation, dissection, and aneurysm. These cardiac manifestations can be identified with echocardiography, computer tomography, and angiography. Standard treatment of an acute hypertensive crisis in Marfan syndrome uses propranolol and sodium nitroprusside. This patient with Marfan syndrome whose case is reported herein presented with chest pain, hypertensive crisis, and aortic insufficiency; labetalol was used successfully to treat the acute hypertensive crisis and magnetic resonance imaging (MRI) was used to differentiate between aortic dissection and an expanding aortic aneurysm. This report is unique in that labetalol was used to control the hypertensive crisis in Marfan syndrome and MRI was used as the initial diagnostic modality in an emergency setting. 