The aim of the study was to assess receptor CD11b and CD62L expression on neutrophils and IL-1beta, IL-6 and IL-8 level in children with ulcerative colitis. Thirty children aged 8-17 years were included in the study. The investigations were performed in the acute phase, prior to the treatment and during remission, 2 months after clinical improvement was obtained. The control group consisted of 12 children with chronic obstipation. IL-1beta, IL-6 and IL-8 serum level and receptor CD11b expression, especially on resting neutrophils, in children with severe and moderate course of the disease were statistically significantly higher; whereas CD62L expression was significantly lower in comparison with the controls and got back to normal during remission. Increased IL-1beta level was observed only in children with severe disease course. In children with mild process the results of the investigations were similar to the control group. In children with severe disease activity the proinflammatory cytokines levels in serum were elevated. The neutrophils in children with severe course of the disease manifested priming in peripheral blood before leaving the circulation.