Spinal MRI was performed in 9 multiple myeloma and 2 solitary plasmacytoma, using sagittal, T 1-weighted (TR: 350-550 ms/TE: 15-26 ms) and T 2-weighted (TR: 2,000-2,500 ms/TE: 60-120 ms) sequences, with additional gadolinium injection in 3 cases. MRI features were the following: 1) round, patchy lesions with low T 1 signal highlighted by gadolinium and bright T 2 signal were present in 10 of the 11 patients: all osteolytic lesions seen on plain X-rays corresponded to such lesions and biopsy performed in 4 cases showed massive marrow replacement by plasma cells. 2) overall marrow signal was dramatically decreased in 3 patients (2 of whom had a high tumoral mass). 3) extra-dural compression was present in 4 cases. 4) 25 vertebral compression fractures (10 of whom with a "benign" appearance) and focal fat deposition were seen. 5) postradiation treatment examination seemed predictive of the outcome in the 2 solitary plasmacytomas. MRI proved to be more sensitive than plain X-rays or bone scintigraphy. Number and size of focal tumor-like lesions did not correlate with the low marrow signal appearance. Both correlated poorly with overall tumoral mass but diffuse abnormalities were associated with rapidly fatal outcome in three cases. These features might reflect qualitative rather than quantitative patterns of the disease (nodular or diffuse macroscopic marrow replacement). These findings are in agreement with those of the few previous studies. MRI is valuable for spinal cord damage assessment. It appears less accurate in benign versus malignant vertebral compression fracture determination than it does in bone metastasis. Its prognostic value is still questionable.