Metabolic derangements have been identified in various cardiovascular pathologies, and many metabolic disorders may lead to a cardiac phenotype. Magnetic resonance spectroscopy (MRS) has the unique capability to provide quantitative data on in vivo tissue content of relevant metabolites, and can therefore be of added value to cardiac MRI protocols. Human anatomy and physiology pose substantial challenges to adequately localized MRS of the in vivo heart. This educational will discuss localization strategies for MRS of the in vivo heart, consider aspects for a meaningful quantitative interpretation of acquired spectra, and highlight various applications of proton, phosphorus-31 and carbon-13 MRS.