PURPOSE: To evaluate the MRI findings and usefulness of MRI for the differential diagnosis of tuberculous and pyogenic spondylitis. MATERIALS AND METHODS: MRI was performed in a total of 38 patients in whom tuberculous spondylitis (n=27) and pyogenic spondylitis (n=11) had been pathologically confirmed. Using T1WI, T2*WI and gadolinium-DTPA T1WI, MRI findings of vertebral collapse, involvement of paraspinal soft tissue and marginal configuration, subligamentous extension and enhancement pattern were retrospectively investigated. RESULTS: Infected lesions were identified by observing signal change on T1WI and T2*WI. In tuberculous spondylitis, vertebral collapse (seen in 85.2% of cases), subligamentous extension (92.5%) and rim enhancement (92.6%) were more common than in pyogenic spondylitis; a diffuse enhancement pattern was more commonly observed in pyogenic (100%) than in tuberculous spondylitis (7.4%), however. The involvement of paraspinal soft tissue was more extensive, smooth and well marginated in tuberculous than in pyogenic spondylitis, though involvement of the vertebral cortex and disc was more prevalent in pyogenic than in tuberculous spondylitis. CONCLUSION: MRI is one of the better modalities for differential diagnosis of tuberculous and pyogenic spondylitis and for early and accurate treatment of either disease.