The need for better methods than the conventional clinical, biochemical and radiographical examinations in the management of inflammatory joint diseases is evident, since these methods are not sensitive or specific to early pathologies and subtle changes. Magnetic resonance imaging (MRI) offers improved sensitivity to early inflammatory and destructive changes in peripheral joints in rheumatoid arthritis (RA) and, even though less well documented, in other inflammatory joint diseases. Good evidence is available that MRI bone erosions represent true bone abnormalities and are predictors of radiographical outcome in RA. Similarly, there is solid evidence for MRI synovitis representing true synovial inflammation and being of considerable practical, clinical and radiological significance in RA. Describing the encouraging current knowledge regarding MRI for diagnosis, monitoring and prognosis, this chapter discusses the potential for the use of MRI in the clinical management of patients with suspected and diagnosed inflammatory joint diseases, as well as research priorities and clinical situations where the use of MRI could be suggested