Ultrasound examination is becoming more and more common in patients with rheumatoid diseases. Above all, it enables the assessment of articular soft tissues and constitutes a non-invasive examination. In a rheumatologist’s everyday practice, it is conducted at the stage of initial diagnosis as well as to monitor the treatment and to confirm the remission if the clinical picture is ambiguous. The first sign of arthritis (including rheumatoid arthritis) that is visible on ultrasound examination is the thickening of the synovial membrane of the joint cavities, tendon sheaths or bursae. It is frequently accompanied by the exudate in the joint, sheath or bursa. In a subsequent stage, in Doppler examination, enhanced vascularization of the synovial membrane is observed. Sometimes, the inflammatory process of the tendon sheaths also affects the tendons, which might lead to their damage. Moreover, ultrasound examination also reveals erosions and inflammatory cysts (geodes) which attest to the advancement of the disease. A dynamic ultrasound examination enables to diagnose the capsule-ligamentous contracture of the interphalangeal joints, which occurs due to the lack of rehabilitation that should begin at the moment of the commencement of the inflammation. The ultrasound image does not allow for the differentiation between various rheumatoid entities, including those encompassing the joints in the hand, wrist. The observed changes, i.e. thickening of the synovial membrane, hyperemia, effusions, erosions or tendon damage, may accompany various rheumatoid entities. The purpose of the ultrasound examination is to recognize these irregularities, determine their localization and advancement and, finally, to monitor the course of treatment. Furthermore, ultrasound scan enables to assess the joints and tendons in a dynamic examination in relation to local ailments of the patient as well as to monitor the biopsy, aspiration and medicine administration. Sonography is used for a US-guided administration of radioisotope substances for synoviorthesis.