The purpose of this study is to evaluate the effectiveness of the treatment of juvenile idiopathic arthritis with systemic manifestations with interleukin-1 (IL-1) inhibitors. Material and methods. A prospective analysis of the course of systemic juvenile idiopathic arthritis was performed in a 15-year-old patient; she was examined using laboratory and instrumental methods before and after therapy with the interleukin-1 (IL-1) inhibitor canakinumab. Laboratory examination included general and biochemical blood tests, determination of rheumatoid factor, C-reactive protein, lactate dehydrogenase, procalcitonin, antinuclear antibodies, anti-citrullinated peptide (ACCP) antibody titer, antistreptolysin-O titer. The patient underwent ECG, echocardiography (EchoCG), ultrasound examination of the pleural cavities, abdominal organs, kidneys, knee joints, radiography of the chest cavity organs and radiography of the hand, computed tomography of the chest and abdominal cavities. Results. Examination of the patient revealed: synovitis of the knee joints, bilateral pleurisy and pericarditis, positive markers of the inflammatory process, characteristic of juvenile idiopathic arthritis with systemic manifestations. The patient was diagnosed with leukocytosis up to 20.3×109/l with a stab shift of leukocytes up to 18%, an increase in the erythrocyte sedimentation rate of 55 mm/h, an increase in C-reactive protein up to 288 mg/l, lactate dehydrogenase up to 500 units/l, in the analyzes urine revealed moderate hematuria and proteinuria. X-ray examination revealed structural changes in the knee and interphalangeal joints. We observed the effectiveness of canakinumab therapy. During therapy with canakinumab, after the second injection, positive dynamics was noted: leukocytes 5.1 × 109/l, ESR 6 mm/h, CRP 12 mg/l, relief of symptoms of the disease. Conclusions. During therapy with canakinumab, the patient showed positive clinical and laboratory dynamics of the disease. The study demonstrated the effectiveness of interleukin-1 (IL-1) inhibitors, canakinumab, in achieving remission of the disease.