This report reviews imaging methods used for diagnosis and monitoring of rheumatoid arthritis, with emphasis on the role of ultrasonography. Traditionally, conventional radiography has been useful in detecting and monitoring the extent of joint destruction in rheumatic disease. However, it is particularly difficult to detect pathological joint changes in the early stages. Magnetic resonance imaging is able to detect inflammation of the synovial membrane and erosions but is limited by cost and availability. Ultrasound has recently emerged as a useful and potentially reliable method for assessing the degree of joint inflammation and erosion in patients with early rheumatoid arthritis.