Imaging of inflammatory disorders of the spine and sacro-iliac joints is important for the diagnosis, prognosis, and evaluation of therapy. Conventional radiography still constitutes the basic imaging modality, but supplementary computed tomography (CT) and especially magnetic resonance imaging (MR-scanning) may provide additional important information. The radiation dose by CT must be taken into account. It is therefore expected that MR-scanning, which is without known risks, will increasingly become the method of choice when the information obtained by conventional radiography is inadequate.