Background:The disease known as juvenile idiopathic arthritis (JIA) is an idiopathic inflammatory condition that mostly affects joints, targeting extraarticular tissue as well as the synovium. The present study assessed the role of power doppler sonography in knee involvement in patients with juvenile idiopathic arthritis (JIA). Materials & Methods:75 patients with juvenile idiopathic arthritis (JIA) of both genders were selected. The knee joints were evaluated with plain radiography, US, and colordoppler. Results: Knee score was 3.2, 3.7 and 4.2 in group I, II and III respectively. The mean morning stiffness was 74.6 minutes, 57.4 minutes and 72.3 minutes, JAFAR score was 6.6, 10.7 and 11.9 and plain radiography score was 6.5, 6.0 and 7.2 respectively. The difference was significant (P< 0.05). The mean synovial thickness was 1.2 cm, 0.9 cm and 1.0 cm in group I, II and III. The effusion volume was 2.8 ml, 3.1 ml and 4.9 ml, loculation of effusion was seen in 0, 2 and 5, C of medial condyle thickness was 3.6 mm, 2.9 and 2.7 and C of lateral condyle thickness was 2.5, 2.8 and 2.6 and Cartilage IE was seen in 1, 3 and 5 respectively. The difference was significant (P< 0.05). Conclusion: Doppler sonography as a non-invasive, low-cost, and readily available tool for the assessment of articular involvement in knees of JIA patients.