The experience with magnetic resonance imaging (MRI) of 81 patients with primary bone tumours and tumour-like lesions is reported. MRI proved to be a sensitive method of detecting primary bone tumours. Intramedullary and extraosseous parts of bone tumours were delineated better than by plain films and computed tomography (CT). Surgical clips and Harrington rods did not appreciably limit the estimation of tumour recurrence. MRI provided definite advantages compared to CT in the surgical staging of bone tumours and tumour-like lesions. MRI was found to be an imaging method with low specificity. Differentiation of tissue components, such as haematoma, fat, necrosis, and cystic areas, led to a specific diagnosis only in rare cases. Plain films and CT were found to be superior to MRI in assessing the biological activity and the differential diagnosis of bone tumours and tumour-like lesions.