Introduction. Juvenile idiopathic arthritis (JIA) is a persistent type of arthritis with no defined cause that starts before the age of 16 years and lasts for at least 6 weeks. The objective of the study was to determine the clinical and laboratory efficacy of tocilizumab treatment in patients with systemic and polyarticular seropositive forms of JIA. Material and methods. The study took place in the Division of Rheumatology, Public Healthcare Institution – Mother and Child Institute, Chisinau, Republic of Moldova. The parents of the patients signed the written consent to participate in the study. The study was approved by the Ethics Committee of the institute. The inclusion criteria for enrolling the patients who underwent the biological treatment were both the systemic and polyarticular JIA forms (seronegative or positive) and active sacroiliitis. The exclusion criteria were the patients with active infections, tuberculosis, sepsis, malignancies, and immunodeficiency disorders. This study included 20 children with JIA, in whom tocilizumab was administered every two weeks. The number of painful joints, the number of swollen joints, and the global evaluation of the disease by the doctor (GEDD) and by the patient (GEDP), as well as via the Childhood Health Assessment Questionnaire (CHAQ), were determined. Furthermore, paraclinical tests, that included complete blood count and C-reactive protein (CRP), were determined. Results. Children treated with tocilizumab exhibited a decreased number of painful and swollen joints, as well as the GEDD, GEDP, and CHAQ scores. Moreover, a decrease of the erythrocyte sedimentation rate (ESR) and CRP was observed. Conclusions. Children with JIA treated with tocilizumab showed a considerable clinical improvement and the paraclinical indices revealed a lower active inflammatory response.