PURPOSE: To obtain magnetization transfer ratio(MTR) of the annulus fibrosus and nucleus pulposus and to assess the feasibility of utilizing the changes of these MTRs as an early indicator of disk degeneration. MATERIALS AND METHODS: MR images of lumbar spine with magnetization transfer(MT) technique in 42 patients were obtained. spin echo techniques (600/14) with same TR/TE with 1KHz off-resonance saturation were employed in 1.0T MR system. MTRs were calculated in two regions, anterior annulus fibrosus and nucleus pulposus, and the results were compared between the normal and degenerative disks, from grade I to IV, on T2-weighted images. RESULTS: MTRs of the nucleus pulposus were 17.6% in the normal disks, and 26.7%, 28.4%, 29.1%, 29.7% in degenerative disks, from grade I to IV, respectively, with a significant difference(P<0.05). On the other hand, MTRs in the annulus fibrosus were 30.2% in the normal disks and 31.5%, 33.2%, 32.1% and 35.6% in degenerative disks, from grade I to IV, respectively, without significant difference. CONCLUSION: Since MTRs are significantly higher in degenerative nucleus pulposus than those of the normal disks, increased MTRs in the nucleus pulposus can be used as an early sign of the degeneration of the nucleus pulposus.