Introduction. Severe bacterial infections and bacterial sepsis remain one of the most topical problems in modern medicine. Stable high lethal outcome and continuous tendency to the growth of sickness rate are often caused by untimely making the diagnosis and administration of treatment respectively. In recent years C-reactive protein (CRP) and other proteins of acute inflammatory phase are used as biomarkers to diagnose sepsis. At the same time the problem of early diagnostics of purulent-septic diseases in infants cannot be considered completely solved. Objective. To improve diagnostics and treatment of generalized purulent-septic diseases in children, diagnostic and prognostic value of clinical-paraclinical signs in sick infants should be studied. Materials and methods. 19 infants hospitalized in the infectious department for infants of Chernivtsi Regional Pediatric Clinical Hospital (RPCH) for generalized infectious-inflammatory diseases were examined. The group of comparison included 29 infants with various somatic pathology (anemia, energy-protein insufficiency, rickets etc.). In addition to generally excepted methods all the infants underwent a comprehensive clinical-paraclinical examination including immunologic tests of I-II levels, detection of protein content of acute inflammatory phase. Results of the study. A high specificity and at the same time low sensitivity of the peripheral blood leukocytosis more than 10,5 g/L and stab neutrophil shifting of leukogram more than 12% to confirm sepsis of infants were found. The content of immunoglobulin G more than 10,0 g/L in the blood serum was characterized by a high specificity as well, although unreliable signs of clinical-epidemic risk. The content of C-reactive protein more than 10,0 mg/L in the blood serum of patients with sepsis was found in 72,0% of cases, the content of α-1-antitrypsin more than 3,7 g/L in the blood serum – in 71,4%, and concentration of ferritin over 54,0 ng/ml – in 80% of children. In the group of comparison the concentration of proteins in acute inflammatory phase was found in 35,7; 45,5 and 25,5% respectively (рφ 10 mg/ml and ferritin>54,0 ng/ml in the blood serum of infants was 4,7 and 12,0 respectively with 95% confidence interval (CI 1,3-17,1 and 0,2-181,0; χ2=10,9 and 10,0), which proved statistical reliability of the paraclinical changes indicated. None of the mentioned paraclinical signs taken separately is characterized by a high sensitivity and specificity in the diagnostics of sepsis in infants, and it requires a necessity of a comprehensive diagnostic approach. Considering the results obtained, we suggested to use a diagnostic pair of clinical-paraclinical signs to diagnose sepsis in infants: the results of spontaneous variant of nitro blue tetrazolium (NBT) test of neutrophil granulocytes in the blood increasing 17% of formazan-positive cells, and the content of C-reactive protein of the blood serum 10 mg/ml and more. There are the following indices of diagnostics value of the suggested complex of examinations: specificity – 64,0%, sensitivity – 92,0%, predicted value of a positive result – 75%, predicted value of a negative result – 88,0%. An attributive risk of septic process in infants with the indices mentioned was 62,0%, a relative risk – 5,7, and the correlation of chances was 2. Conclusions. 1.To diagnose sepsis in infants a comprehensive approach should be used, because none of separately taken clinical-paraclinical signs is characterized by synchronous high indices of diagnostic value and reliable risk of present generalized purulent-septic disease. 2.With the aim to find sepsis in infants a diagnostics complex of paraclinical signs is recommended to be used: the content of 17,0% and more of formazan-positive neutrophils in spontaneous NBT-test in combination with the values of C-reactive protein content in the blood serum of 10,0 mg and more.