The present review provides an update of the available data and discusses research issues relating to ultrasound (US) imaging in osteoarthritis (OA). Currently, the principal indications for using US in OA include: delineation of changes within articular cartilage (AC) and demonstration of synovial and adjacent soft tissue pathology together with injection into OA joints under US guidance. US has been proposed as a possible imaging tool for following the progression of OA. The main priorities requiring the attention of researchers include: addressing difficulties surrounding consensus on definitions of pathology in OA, charting the natural history of AC change in site specific OA, investigation of the link between inflammation and OA and the use of three-dimensional (3D) US in OA.