Objectives: To evaluate, using musculoskeletal ultrasound (MSUS), the effects of Etanercept therapy in patients with rheumatoid arthritis (RA) over 3 months of treatment. Methods: Eighteen consecutive patients, 3 male and 15 female, affected by RA (ACR criteria) who were non-responders or partial responders to DMARDs therapy were commenced on Etanercept treatment. MSUS was performed bilaterally in the 2nd and 5th metacarpophalangeal, 3rd interphalangeal, wrist and knee joints, using a Philips/HP Image Point HX machine with a 7,5 MHz linear probe for knee joints and a 14 MHz probe for the hands and wrists. In addition, power Doppler was used with the following settings: PRF 700-1000Hz, gain 60-65 dB, low filter. For all the changes a semi-quantitative score (0-3) was used to indicate the presence of a localised inflammatory process (synovitis, tenosynovitis). An overall score was then calculated based on the sum of the single scores in order to obtain a comprehensive score indicative of the global pathological change. Results: The overall score significantly (p<10-5) reduced between T0 (8,5) and T3 (5). Even the most part of the local joint scores significantly reduced. Conclusions: a positive response to treatment with Etanercept was demonstrated by MSUS examination of several joints. The results of our study are supportive of those presented in other reports where MSUS was used to monitor disease activity. We were able however to demonstrate this in a wider range of anatomical targets than in previous studies. MSUS is a useful tool in the monitoring of biologic therapy in RA.