The immunoinflammatory pathogenesis of juvenile chronic arthritis (JCA) involves the activation of many pathways including various cytokines. We have evaluated the levels of interleukin(IL)-1, IL-6 and IL-8 in 29 JCA patients. The age range was 1-16 with a mean of 10.1. A disease activity score was developed on the basis of: 1. constitutional symptoms and/or morning stiffness, 2. presence of joint swelling, 3.warmth, 4.limited range of motion, and 5.joint pain. This score correlated very significantly with laboratory disease activity markers such as erythrocyte sedimentation rate (ESR) and CRP (both p = 0.006) and also correlated with IL-1 and IL-6 levels. The levels of IL-1 decreased in four of the five patients with improved disease activity. IL-6 but not IL-1 correlated significantly with the number of inflamed joints (p = 0.013); IL-6 also strongly correlated with rheumatoid factor supporting this cytokine's role in B cell induction (p = 0). Haemoglobin values correlated negatively with the activity index, ESR, CRP, IL-1 and IL-6. IL-8 did not correlate with disease activity markers. In the systemic patients all cytokines tended to be higher. Our data suggest that interleukins 1 and 6 are effective in the pathogenesis of JCA. Whether cytokines may be used for monitoring therapy may be clarified with further studies.