Predictors of positive virological response to interferon therapy in children have not been established, which is why it is necessary to identify them and subsequently develop individualized treatment regimens yielding the best possible results. Objective: form personalized chronic hepatitis C treatment regimens in children on the basis of identification of virological response predictors and retrospective evaluation of the conducted interferon therapy efficiency. Study participants: 98 children of 3-18 years of age (mean age – 10.0±0.8 years) with chronic hepatitis C: 65 of them had HCV 1 genotype (66.0%), 33 – HCV 2-3 genotype (34.0%). We measured anthropometric parameters (weight, height), determined viral load level in blood serum (polymerase chain reaction (PCR)), performed HCV genotyping (before the therapy) and analyzed lymphocytic immunophenotype parameters of all children before the interferon therapy course and over time (4, 12, 24 and 48 weeks after the therapy initiation). Results: Analysis of the obtained results demonstrated that the recombinant IFNα-2a therapy efficiency improves if recombinant IL2 (roncoleukin) is added to the treatment regimen: double increase in the rate of achievement of the primary virological remission (PVR) and sustained virological response (SVR) (p < 0.05). Use of a pegylated IFNα-2b in combination with ribavirin did not yield any significant difference in comparison with treatment with recombinant IFNα-2a and recombinant IL2. Interferon therapy is more effective in children of at least 30 kg of body weight and 134 cm of height without physical developmental delay than in younger children (of smaller weight and height) at the moment of interferon therapy initiation (p < 0.001). Thus, anthropometric parameters of patients may serve as PVR predictors regardless of the HCV genotype at the treatment initiation. If lymphocytes ≥ 2,500/mcl, the PVR achievement rate is 85.0%; if lymphocytes ≤ 2,000/mcl – 5.0% (p = 0.000). If the total amount of lymphocytes is 2,000-2,500, the examination should be repeated 12 weeks after the therapy initiation: increase in the number of lymphocytes in comparison with the initial values by 10.0% or more is positive prognostic SVR predictor. Conclusions: It is necessary to take into consideration parametric data and the child’s age at the moment of therapy initiation in order to schedule the launch of interferon therapy and choose a therapy regimen for chronic viral hepatitis C in children. Total amount of blood lymphocytes, child’s body weight and height at the moment of treatment initiation are predictors of positive virological response to treatment.