Rheumatoid arthritis (RA) is chronic rheumatic disorder leading to joint inflammation and potential structural damages. This destruction occurs early in the disease outcome leading to the concept of window of opportunity. New diagnosis RA criteria have been proposed to allow an earlier diagnosis and subsequently a better management of the disease. Moreover, tight control of the disease was able to improve the prognosis of RA. For this, rheumatologists need routinely feasible tools and ultrasound (US) appears as the ideal imaging modality. US is superior to clinical exam for the detection of subclinical synovitis. US has a good correlation with clinical findings and markers of inflammation. US persistence of synovitis is associated with higher rate of relapse and more radiographic progression. However, standardization of scoring and settings procedures is necessary before being universally accepted as a marker of disease activity. Finally, US did not improve the tight control strategy and did not replace clinical exam for RA management.