Ultrasound (US) is a valuable imaging modality in the evaluation of joint and periarticular abnormalities in osteoarthritis (OA). It is able to image structural lesions as well as inflammatory changes in early and late disease. US is a relatively inexpensive, safe and quick-to-perform tool that can be used as a bedside procedure in the assessment of patients with OA. US shows abnormalities at different peripheral joint sites that can be assessed for variable aspects during the same scanning session. The easy accessibility of equipment facilitates its use and applications in the clinical practice. US is helpful in guiding local procedures (i.e. aspirations of joint and periarticular fluid collections, drug injections, biopsy) that can be easily and safely performed with optimal patient's tolerance. In addition, US allows for a monitoring of the disease process and follow-up of local and systemic treatments.