Proton magnetic resonance spectroscopy (MRS) permits in vivo determination of biochemical parameters within brain tissue, utilizing the same magnetic resonance (MR) scanner and head coil that are utilized for conventional MR imaging. This technology has been evolving and improving over the past decade, with most of the current published work based on the measurement of rather large single voxels, utilizing variable echo times, aimed at characterizing changes in brain tumors, demyelinating diseases, abscesses, and metabolic diseases. Future work will utilize multiple-voxel techniques so that volumes of tissue can be examined with smaller voxels in reasonable acquisition times, providing a greater understanding of the metabolite composition of the brain, especially as more and more metabolites are identified within the spectra.