Objective: To study blood lactate levels at admission in predicting mortality in critically ill children requiring haemodynamic / respiratory support.Method: A prospective observational study was done in 200 critically ill admissions to the paediatric intensive care unit (PICU), requiring haemodynamic / respiratory support. The demographic data, clinical status, organ involvement and therapeutic interventions were recorded in a predesigned proforma until hospital discharge or death. Lactate levels were estimated at admission and were correlated with the mortality and organ dysfunction Results:The geometric mean of lactate levels at admission in survivors and non survivors were 20.58 mg/dl and 50.48 mg/dl respectively. Blood lactate was 82.9% sensitive and 85.4% specific at the optimal cut-off value of 33.7 mg/dl. The positive likelihood ratio was 5.67 and the negative likelihood ratio 0.2. Conclusions:Blood lactate levels at admission predict mortality in critically ill children requiring haemodynamic/respiratory support.