OBJECTIVES: Advances in ultrasound technology and training have made it possible for physicians to conduct detailed imaging studies in an office setting.  Ultrasound images make it possible to visualize subclinical evidence of disease activity quickly and could contribute to prompt initiation of therapy in patients with rheumatoid arthritis (RA). The objectives of this study were to describe the use and cost of ultrasound in patients with a confirmed diagnosis of RA, in the United States, over the last decade.     METHODS: Patients were selected from a large national private insurance-claims database if they had at least 2 claims for ICD-9 code 714.xx at least 45 days apart and received Disease-Modifying Antirheumatic Drug therapy between 2002 and 2013.   The CPT codes 7880-7882 were used to identify ultrasound procedures.  Descriptive statistics were used and simple hypothesis tests performed. RESULTS: A cohort of 129,005 patients with RA was selected for this study.  Patients who received ultrasounds were significantly (p < 0.01) more likely to be younger, female, have point-of-service insurance, and live outside the Midwest.   Between 2002 and 2013, there was a >1900% increase in the use of ultrasound in this patient population, from 73 procedures in 2002 to 1448 procedures in 2013.  During this same period, the mean cost of the ultrasound procedure fluctuated over time; the cost increased 35% to a high of $216 (2013 USD)  in 2008 and then decreased starting after 2010 down  32% by 2013 to $146 (2013 USD).  Rheumatologists performed 70% of the procedures.  CONCLUSIONS: This research clearly shows that use of ultrasound, primarily by rheumatologists, has been increasing. The data also show that patients who received ultrasounds may be different than those who did not receive the procedure.    Further research is needed to evaluate the impact ultrasounds may have on treatment decisions, access to biologics, and patient outcomes.