Introduction and aim. With increasing ultrasound US assessment opportunities for tight rheumatoid arthritis (RA) management, more simplified accurate US-assessment is desired in clinical practice. Aim of the work is assessing modified vs simplified ultrasound 6-joint scores relevance in assessing rheumatoid arthritis disease activity. Material and methods. Fifty-five RA patients were subjected to detailed history, clinical, and musculoskeletal examination with disease activity assessment by clinical disease activity index, simple disease activity index and disease activity score in 28 joints. Com plete blood count, erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor, anti-cyclic citrullinated peptide antibodies were done. Patients underwent US examination (gray-scale and power Doppler) for wrist, 2nd and 3rd metacarpophalangeal and knee joints bilaterally. Synovitis composite score was added. Two US indices were constructed: simplified S6 and modified M6 joint scores. Results. Statistical significant positive correlations were high between S6/M6 score parameters (total, grey-scale (GS), power doppler (PD), Composite) and disease activity markers. Both M6 and S6 scores differentiated mild-moderate and moderate-severe disease activity patients. However, only S6 score differentiated remission from mild disease activity patients. Conclusion. Ultrasound 6-joint scores (especially simplified S6) were rapid, easy and sensitive ultrasound tools assessing rheu matoid arthritis disease activity in clinical practice.