In December 1991, the National Cancer Institute held a workshop to evaluate the role of magnetic resonance (MR) spectroscopy in human cancer biology. The clinical and basic cancer research issues requiring use of MR spectroscopy, the advantages and limitations of MR spectroscopy, and future directions in MR spectroscopy of cancer were discussed. Consensus-building panels were formed on the following four topics: cell membrane biochemistry, tumor therapeutic response or drug resistance, appropriate model systems, and potential clinical applications of MR spectroscopy. The workshop members concluded that large prospective clinical studies as well as in vivo animal and human studies to define prognostic variables should be performed, with correlation between MR spectroscopic results and biochemical and physiologic features. Studies of phospholipid metabolism, the pharmacokinetics of anticancer agents, and effects of new cancer treatments on the tumor vasculature and normal tissues are needed.