Synovial hypertrophy, effusion, and articular cartilage status were evaluated with gadolinium tetraazacyclododecanetetraacetic acid (DOTA)-enhanced magnetic resonance (MR) imaging in 24 knees in 24 pediatric patients (17 female, seven male; mean age, 10 years; range, 3-18 years) with juvenile rheumatoid arthritis (JRA). T1-weighted spin-echo sequences were performed with a 0.5-T unit before and immediately after injection of Gd-DOTA (0.1 mmol/kg). Substantial enhancement of synovial proliferation was seen in 23 of 24 knees, allowing precise assessment of pannus extension (n = 23), joint effusion (n = 21), cartilage loss (n = 21), and meniscal hypotrophy (n = 23). On T1-weighted images without contrast enhancement, cartilage thickness, loculation of joint effusion, and pannus extension were underestimated. Thus, Gd-DOTA-enhanced MR imaging is mandatory in the assessment of knee involvement in children with JRA and may prove to be useful in the evaluation of response to therapy.