In summary, MRS is a powerful tool for the noninvasive measurement of tissue metabolism and pH. 31P MRS measures high-energy phosphates and pH, 1H MRS measures carbon metabolism, and 14N detects nitrogenous compounds. Studies with perfused organs in experimental animals suggests that MRS has potential for noninvasive monitoring of the human kidney in health and disease. The production of large magnet systems which accommodate human subjects raises the possibility that MRS may be used for clinical diagnosis. There are several problems concerning the application of this technology to the investigation of human renal metabolism. Nevertheless, because this field is advancing so rapidly, it can be expected that within the next few years MRS will be used to study human kidneys in health and disease. Whether or not MRS proves to be a useful diagnostic tool in clinical medicine remains to be determined.