MR imaging has had an unparalleled impact on the treatment of patients with musculoskeletal sarcoma. Basically, the high accuracy of local staging has made the introduction of reconstructive and limb salvage procedures instead of amputation of disarticulation available to the majority of patients with musculoskeletal sarcoma. Pre-operative work-up with MRI is not only more accurate, but also much faster and cheaper than the conventional work-up. Staging is the single most important reason for performing MR imaging in patients with musculoskeletal tumours. The impact of MR specificity is less dramatic but the benefit to the patient is an increased safety margin. When diagnostic errors with devastating consequences are made nowadays, it is usually because the proper protocol has not been followed. A patient with a potentially malignant, or equivocal, musculoskeletal mass deserves to have a combined radiographic-MRI examination prior to invasive procedures. MRI does not currently have a major impact on chemotherapy decisions and colour Doppler ultrasound has a higher accuracy than MRI. However, selected cases, i.e. intraosseous tumours, dynamic Gd-enhanced MRI, can replace colour Doppler ultrasound.