Effectiveness of nuclear magnetic resonance imaging (MRI) was compared with that of the CT scan in several cases involving different lesions: intracranial, base of skull, facial sinuses, parapharyngeal spaces. MRI provided excellent contrast in soft tissues with good detection of tumors and their limits, the condition of neighboring tissues and any local or regional tumor extension. Vessels were also visualized. It was not influenced by dental artefacts, and allowed three-dimensional sections to be obtained simply without manipulation of patients. In contrast, bone structures were analyzed less clearly than by the CT scan. Marked progress in MRI technical features and results obtained can be expected in the very near future.