Introduction: Lactate is a normal end product of carbohydrate metabolism, other processes, unrelated to tissue hypoxia, may also cause lactate levels to rise. Blood lactate levels are used in shock patients, both for detection of hypoperfusion and adequacy of resuscitation. Tissue perfusion is the oxygen supplied at the tissue level to support normal aerobic cellular metabolism. Inadequacy of tissue perfusion causes increase in lactate levels. It reflects severity of illness with significant prognostic implications Material and Method : The study was conducted at Paediatrics Intensive Care Unit (PICU) from from October 2016 to September 2018y at SVP PG IP and S C B Medical College, Cuttack. This study was a prospective observational study. Result: Mortality in septic shock patients with hyperlactatemia was high (39%). The mean age of the hyperlactatemic group was 30.7 months with a M:F ratio of (1.9:1). The mean lactate level at admission, 6 hr and 24hr among survivor and non survivors were (4.13±1.1, 3.02±0.8,1.61±1.0 mmol/l) and (6.25±4.1, 5.98±1.15,3.65±2.3mmol) with (p=0.001) which is significant. Mean PRISM III score among survivors and non survivors were 5.9±3.0 and 15.63±4.1 with p=0.001 was a significant difference. Conclusion: Septic shock is a common cause for PICU admission with high mortality. This study demonstrated that most patients who died had higher blood lactate level than survivors at presentation.