MR angiography using a gradient-echo, pulse sequence FLASH (fast, low-angle shot) method during breath-hold with a "MAGNETOM H-15" scanner (1.5 Tesla; Siemens Medical System) was performed on 27 patients with renal tumor at our clinic between February 20, 1990 and September 30, 1991 and we studied to evaluate its usefulness. Of these 27 patients, 22 patients including one patient under hemodialysis treatment had renal cell carcinoma and one patient had oncocytoma pathologically proven from the excised specimens. The remaining four patients including two patients associated with inferior vena caval tumor thrombus were clinically diagnosed as renal cell carcinoma based on the result of imaging examinations such as excretory urography, ultrasonography, computed tomography and conventional angiography. However, they could not be operated on because their tumors were too advanced. By reconstruction of the data of consecutive coronal scans of the abdomen with Maximum Intensity Projection (MIP), the MR angiography could in all cases delineate abdominal blood vessels such as the abdominal aorta, inferior vena cava and renal arteries and veins simultaneously without any intravenous contract materials. Our present study revealed that MR angiography has some advantages, especially with regard to preoperative angiographic information about the abdomen of patients with renal tumor. That is, MR angiography can delineate many kinds of arteries and veins of the abdomen simultaneously and in a broader range, as well as it can be performed on the patients with hypersensitivity to iodinated contrast materials or renal insufficiency in a usual fashion.(ABSTRACT TRUNCATED AT 250 WORDS)