The physical principles of nuclear magnetic resonance (NMR) imaging were initially outlined. In the present proton images, T1 and T2 relaxation times were more important than proton density in determining the varying intensity of the tissue. Early clinical experiences of NMR for malignancies of the head and neck region, chest, abdomen, pelvis and extremities were also presented. There was superb ability for soft tissue characterizations, accentuating intensity difference between tissues with different T1 and T2 relaxation time. Although the spatial resolution of NMR-CT appeared to be inferior to X-CT, the absence of streak artifacts or X-ray beam hardening were advantageous. Because of the absence of significant NMR signal from rapidly flowing blood, the differentiation of vessels and soft tissue masses was easily accomplished by NMR-CT without employing contrast material. Multisection scans were performed in most cases with not only transverse but sagittal or coronal imaging by simply varying the sequence of pulse gradient magnetic field. While more experience is required, NMR-CT has a promising future in the imaging modality for malignancies.