PURPOSE: To compare MR myelography(MRM) using heavily T2 weighted fast spin echo(FSE) with conventional myelography in the evaluation of lumbar degenerative disc diseases. MATERIALS AND METHODS: A total of 50 patientswith lumbar degenerative disc diseases underwent both MRM and conventional myelography. A 1.5 T Signa MR systemwas used. For MRM, heavily T2 weighted FSE pulse sequences were performed in sagittal, coronal and both obliqueplanes. The images of MRM and conventional myelography were analyzed retrospectively and compared, focusing on the pattern of compression of the thecal sac and nerve roots. RESULTS: MRM yielded comparable images to conventional myelography in 68% (34/50). MRM was superior to conventional myelography in 11 cases (22%), and the opposite resulted in 5 cases(10%). MRM could visualize the spinal canal below the level of complete block in 6 patients,provided better contrast in the cases of dural ectasia in 3 cases and better delineation of individual nerve roots with source images in 1 case. Additional informations such as incidental retroperitoneal vascular malformation and extravasation of the CSF could be obtained by MRM in 1 case each. Disadvantages of MRM were poor contrast in thecases of multiple spinal stenosis, obscuration of the nerve roots by engorged paraspinal vessels, and occassional difficulty in defining the levels due to vanishment of the bony background image. CONCLUSION: MRM is a safe, noninvasive, nonionizing modality which in very effective in evaluating the lumbosacral disc disease. Use ofFSE-MRM in addition to the routine MR imaging could be very helpful not only for better evaluation of nerve roots but also for the additional informations.