MR images of the kidney have been reported in a variety of diseases. The images have been proton scans, usually produced with pulse sequences that have provided a variety of T1- and T2-weighted images. Anatomy is well depicted: renal parenchyma can be easily separated from adjacent organs and surrounding fat, cortex and medulla are distinguishable, and renal vessels and calyces can be identified and distinguished. Focal diseases can be diagnosed: cysts can usually be distinguished from tumors, and varying degrees of hemorrhage in the former may be detected. Renal carcinoma can be staged relatively well and distinguished from angiomyolipomas. Generalized parenchymal diseases may be detected, but data is scanty. There is promise that ATN and rejection may be distinguishable in transplanted kidneys. Changes have been seen in acute vascular diseases, but extensive experience in man is lacking.