Rheumatoid arthritis (RA) is a chronic systemic connective tissue disease which is characterized by symetrical multiple joints involvement and extra-articular symptoms. Current EULAR diagnostic criteria for RA include disease activity parameters, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), which are used to calculate disease activity scores, including DAS and DAS28. Recently attempts have been made to assess disease activity using imaging diagnostic modalities, such as magnetic resonance imaging (MRI) and ultrasonography (US). Due to significant progress in therapy effectiveness and early RA diagnosis possibility, imaging modalities become increasingly meaningful and many clinical trials confirm their usefulness. However, there are no consistent criteria for objective assessment of therapy effectiveness based on US. Moreover, it is not US availability that limits its common use, but rather significant variability between operators. This is why US remains only an additional tool to assess therapy efficacy with regard to DAS/DAS28 index.