Ultrasound (US) is a valid and reliable imaging tool for evaluation of joint and tendon inflammation as well as cartilage and erosions in patients with rheumatoid arthritis (RA). Synovitis is usually scored semiquantitatively for both gray scale synovitis and power Doppler activity, and use of an atlas for US scoring has shown excellent reliability. Several scores are shown to be responsive to medical treatment, but the optimal joint/tendon score is to be explored. Doppler activity may be quantified by use of pixel counts and flow may be examined by use of resistive index. US-guided injections are better tolerated and have increased efficacy, as compared with palpation guidance, and should thus be included in rheumatologic practice. Different methods such as three-dimensional US, contrast-enhanced US and fusion imaging methods are all possible US approaches that may be used in treatment of RA patients in the future.