STUDY DESIGN: This is a retrospective study OBJECTIVES: We wanted to make the early differential diagnosis between tuberculous spondylitis and pyogenic spondylitis according to the clinical and MRI findings. SUMMARY OF THE LITERATURE REVIEW: Making an early differential diagnosis between tuberculous spondylitis and pyogenic spondylitis is essential to start prompt and proper treatment. However, the clinical symptoms and MRI findings of both these illnesses can vary considerably. MATERIAL AND METHOD: Ninety-five patients (49 men and 46 women, mean age: 54.5) who were treated from January 2001 to February 2007 and whose diagnosis was confirmed by laboratory or pathological studies were retrospectively reviewed. 50 patients with tuberculous spondylitis and 45 patients with primary pyogenic spondylitis were included. The patients with combined infection or an uncertain diagnosis were excluded. We compared the medical records and MRI findings between the different groups of patients. RESULTS: The patients with tuberculous spondylitis were younger (48.2 years vs. 61.5 years, respectively) and they had a longer symptom duration (4.3 months vs 1.8 months, respectively). The erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) level were significantly higher in the patients with pyogenic spondylitis (71.3/49.6 mm/hr and5.74/2.98 mg/dl, respectively). A high fever above 38 degree was more frequent in the patients with pyogenic spondylitis. Intraosseous abscess, epidural abscess, a well-definded paraspinal abscess, focal enhancement and severe destruction of the vertebral body on MRI were more frequent in the patients with tuberculous spondylitis. Four parameters such as a symptom duration longer than 3 months, no fever higher than 38 degree, a well-defined paravertebral abscess and an intraosseous abscess were selected. 42 patients in the tuberculous group had 3 or more of these four parameters. The sensitivity and specificity of these combined 4 parameters were 84% and 97.8%, respectively, for making the differential diagnosis between these 2 maladies. CONCLUSION: These diagnostic criteria might be useful to discriminate between tuberculous spondylitis and pyogenic spondylitis even without definite laboratory or pathological results.