Since its establishment in 1985 the Yale Magnetic Resonance Research Center (MRRC) has been a leader in the development and application of MRS technology and 13C isotopic labeling strategies for studying carbohydrate and lipid metabolism in insulin resistance. Much of the initial support for the development of the MRRC core research program came from NIDDK. Recently the MRRC has moved to a new 30,000 square foot building and has added a new 4.0T human MRS/MRI system dedicated to studying metabolism. The primary aim of the MRS/MRI Core will be to provide comprehensive MRS and MRI support on this system for the projects clinical core. Core services provided are i) MRS and MRI methodology at 4.0T for studying brain liver and muscle mitochondrial function ii) metabolic modeling to obtain metabolic fluxes from MRS measurements, iii) MRS/MR system operation and data analysis, and iv) regular quality control measures to ensure the reliability of the MRS and MRI. In addition to being critical for the success of the program project, the MRS and MRI methodology and quality control procedures implemented by the core will benefit all NIDDK investigators (both within and outside Yale) using the facility.