Many cytokines (e.g. TNF, IL-6, IL-8, IL-17, IL-23) are thought to play a critical role in the inflammatory response as well as in joint cartilage and bone destruction processes. In juvenile idiopathic arthritis (JIA) cytokines are supposed to serve as helpful biomarkers for diagnosis and monitoring of the disease. Proinflammatory cytokines, such as TNF and IL-6, also contribute to the generation and maintenance of inflammatory joint pain. The aim of the pre­sent study was to compare the serum cytokine profile and concentrations in two groups of children: suffering from JIA and with joint pain of unknown causes (arthralgia). In JIA sera concentrations of tested cytokines were positively inter-correlated and the levels of some of them (IL-23 and TNF in oligoarticular and polyarticular subsets, respectively) were significantly elevated in children of pubescent age. By contrast, in children with arthralgia cytokines were produced in an uncoordinated way and their levels did not change in the pubescence period. Despite these differences, both cytokine profile and concentrations were similar in both JIA and arthralgia groups. Therefore, we conclude that arthralgia in children obliges clinicians to perform thorough observation and further diagnosis.