We report a 51/2-year-old boy with juvenile rheumatoid arthritis (JRA) and lower-limb lymphoedema. US, MRI and lymphangiography were performed. Based on the lymphangiographic study, we propose a pathogenesis based on obstruction of normal superficial lymphatic vessels in the affected limb. This is discussed with other pathogenetic factors proposed in the 16 previously reported cases of lymphoedema complicating JRA.