The aim of this study was to assess the suitability of US (ultra-sound examination) as an imaging modality in patients with knee pain. US is a sensitive method in demonstrating small bone erosions, fluid accumulation, bursitis changes in the synovia and tendon structure, and changes in the articular cartilage. US was used to assess symptomatic patients. The findings were compared to those of conventional radiographs and to those of an asymptomatic group. In 38 patients of the symptomatic group, US revealed pathological findings. In the asymptomatic group, nine patients revealed pathologic findings. In the symptomatic group, only 12 patients revealed pathological findings in the radiographs. US can provide an early diagnosis by demonstrating joint effusion - synovial thickening - bony changes, patello-femoral changes, articular cartilage changes, meniscal pathologies, such as meniscal cysts and peripheral tears and lesion of tendon, while plain radiographs are still normal and some lesions such as bursitis and tendonitis and in some cases even articular changes, can be reversible. Sonography is an effective tool for the early diagnosis of knee pain. It can detect various soft tissue pathologies as well as early degenerative changes. The examination is inexpensive, non-invasive, dynamic, rapid and avoids patients' exposure to irradiation.