Magnetic resonance (MR) imaging represents the growth area in radiology at present and for well into the 1990s. It has already established itself as the major emerging technique in neuroradiology. Its apparent risk-free application, noninvasiveness and patient comfort provide wide acceptability. This technique may play an important role in the evaluation of cancer patients. Experience with nearly 2,000 patients over a 32-month period demonstrates MR imaging to allow both a more accurate definition of tumor outline and tumor staging, thanks to its high soft-tissue contrast and multiplanar acquisitions. Moreover, MR imaging proves a valuable procedure for radiation treatment planning. Even though it is beyond realistic expectations to seek complete tissue characterization, MR imaging is likely to be increasingly demanded. With the use of specific paramagnetic contrast agents, this technique will eventually replace computer tomography (CT) in both staging and follow-up of several types of cancer.