Introduction. Patients with the history of neoplastic disease in childhood and adolescence, successfully treated, are at higher risk in terms of their susceptibility to develop other diseases later in their lives. Aim. The purpose of study was to evaluate saliva TNF-α concentration in the children with acute lymphoblastic leukemia with reference to gingival inflammations. Material and methods. The investigation was carried out in the group of 78 children with ALL aged 2-18yrs and analogical in terms of age and gender group of healthy controls. Results. Gingival conditions were expressed as gingival index (GI). In the group of children with ALL mean GI determined in examination 1 was 0.084±0.34, in examination 2 GI=0.007±0.04 and in examination 3 mean GI=0.017±0.13. In the group of healthy controls GI=0.003±0.03. Saliva concentration of TNF-α determined in the group of children with ALL in examination 1 ranged 4.16-135.01pg/ml. In that group in examination 1, mean saliva TNF-α concentration was 36.9±32.6pg/ml. In the group of healthy children mean saliva TNF-α concentration was 52.1±107.64pg/ml. Conclusions. The authors, who observed various increases in the concentrations of TNF-α, IL-1α, IL-6, and IL-8 in the saliva and oral tissues in the patients consider that the proinflammatory cytokines in the saliva present in significantly higher concentrations in the future may have diagnostic and predicative value as replace indices of neoplastic transformations. Monitoring of prognostic factors affecting inflammations of the oral mucosa in children with ALL is likely to prevent complications to standard treatment and prolonged time of anticancer therapy. Early evaluation of those parameters can quicken recovery and strengthen patient's health. Close cooperation between dentists and pediatricians-hematologists is important in maintaining oral health and improve the quality of life of children suffering from neoplastic diseases.