In the last two decades, ultrasound has been fully implemented in the diagnosis and management of rheumatoid arthritis. Several studies have been published that have demonstrated better availability of this technique in the identification of elementary inflammatory joint and tendon injuries, as joint and tendon sheath synovial hypertrophy, joint effusion, and Power Doppler signal. Ultrasonography has good properties to identify changes with different treatments, have predictive value for relapse in patients in clinical remission and in structural damage. Furthermore, ultrasound tools have been developed that allow prospective evaluation of patients. Joint and tendon ultrasound evaluation indexes have been used for disease diagnosis and monitoring. Initially, indexes have been integrated only for joint, but more recently have appeared mixed indexes, integrated for ultrasound evaluation and other types of variables. There are still important objectives to be achieved to complete the development of ultrasound in rheumatoid arthritis, which makes ultrasound a great aid tool in decision-making in clinical practice.