The diagnostic value of MR-imaging is tested on 130 patients with pathological retroperitoneal processes. Improved imaging techniques resulted in a more accurate delineation of tumor extension than seen with CT-imaging. Using a ratio of signal intensity from the adrenal tumors and the liver on T2-weighted images, it is usually possible to differentiate adenomas from metastases, carcinomas or phaeochromocytomas. New indications for renal MR-imaging would be parenchymal renal disease and transplant rejections. Moreover, MR allows visualization of lumbar lymph node-chains in the coronal view corresponding to the situs during surgery, thus, facilitating preoperative orientation for the surgeon.