Fibrosis is a common feature of heart disease and is associated with adverse cardiac remodeling and poor clinical outcome. Because of the lack of routine noninvasive patient-specific tissue characterization tools, the development of new treatment strategies for cardiovascular disease specifically targeting undesired fibrosis in the myocardial wall is slow. Cardiovascular magnetic resonance imaging has developed into the gold-standard tool to assess various aspects of myocardial anatomy and function. In recent years, magnetic resonance imaging has also emerged as a promising technique to fulfill the need for a noninvasive assessment of myocardial fibrosis through the use of Gd-based contrast agents and the quantification of the longitudinal relaxation time T1. This paper reviews the current use of T1 mapping for the assessment of myocardial fibrosis, with particular focus on imaging techniques and their validation.