This review describes recent advances in cardiac magnetic resonance spectroscopy (MRS). MRS allows noninvasive characterization of the metabolic state of cardiac muscle, in both animal and human models. Recent experimental MRS studies have allowed new insights into the essential role of energetics in heart failure. Various new studies suggest a rapidly growing role of MRS for phenotyping new genetically modified mouse models, and recent methodologic advances include development of absolute quantification of high-energy phosphates, measurement of ATP turnover rates and thermodynamic parameters (such as free ADP and free energy change of ATP hydrolysis), and improved acquisition sequences. New patient studies demonstrate the potential value of MRS as a clinical diagnostic tool in patients with ischemic heart disease, heart failure, cardiac transplantation, valve disease, and genetic cardiomyopathy.