Material and methods. The study included 60 children operated on for CHD with cardiopulmonary bypass. Patient age was 99 (10—234) days. The criteria for inclusion in the study were the age of up to 1 year, the planned operation with cardiopulmonary bypass, the initial absence of clinical signs of infection and multiple organ failure, the absence of the need for invasive respiratory support, infusion of inotropic and vasoactive drugs. In the dynamics (before the operation, then on 1, 2, 3 and 6 days after the operation) the levels of PCT, MR-proADM, CT-proAVP and MR-proANP in the blood plasma were determined using a Kryptor compact plus analyzer (Thermo Fisher Scientific, Germany). Results. Before the operation, MR-proADM (cut off 0.84 nmol/L, sensitivity 75%, specificity 74%, AUC ROC 0.75) had a predictive value in relation to the development of infectious complications, as well as MR-proADM (cut off 2.81 nmol/L, sensitivity 76%, specificity 78%, AUC ROC 0.8) and PCT (cut off 3.17 ng/mL, sensitivity 68%, specificity 71%, AUC ROC 0.78) on the 1st day after the surgery. Among the predictors of mechanical ventilation more than 72 hours MR-proADM (cut off 0.82 nmol/L, sensitivity 73%, specificity 74%, AUC ROC 0.79) had the greatest prognostic value at the preoperative stage, and MR-proANP (cut off 476 pmol/L, sensitivity 70%, specificity 72%, AUC ROC 0.81) and MR-proADM (cut off 2.44 nmol/L, sensitivity 78%, specificity 81%, AUC ROC 0.74) — on the 1st day after the surgery. In relation to stay in the ICU after surgery more than 7 days MR-proADM (cut off 0.82 nmol/L, sensitivity 70%, specificity 74%, AUC ROC 0.71) had the highest predictive value before the operation, and MR-proANP (cut off 360 pmol/L, sensitivity 73%, specificity 74%, AUC ROC 0.83) and MR-proADM (cut off 2.4 nmol/L, sensitivity 67%, specificity 68%, AUC ROC 0.75) — on the 1st day after the surgery. As predictors of multiorgan failure, MR-proADM (cut off 0.93 nmol/L, sensitivity 63%, specificity 65%, AUC ROC 0.74) had the highest predictive value before the operation, and MR-proADM (cut off 3.28 nmol/L, sensitivity 78%, specificity 80%, AUC ROC 0.89) and PCT (cut off 6.7 ng/mL, sensitivity 73%, specificity 76%, AUC ROC 0.84) — on the 1st day after the surgery. Conclusion. The use of biomarkers makes it possible to predict a complicated postoperative period during the preoperative stage and in the early periods after the operation. MR-proADM has the highest predictive value in children of the first year of life with CHD