Severe sepsis and septic shock are the major causes of morbidity and mortality in the PICU, killing at least one in four. In order to monitor the metabolic consequences of shock and hemodynamic management, plasma lactate levels and standard base excess are being used in critical illness. Goal: To determine plasma lactate and base excess levels in sepsis and septic shock patients at the time of admission to the PICU; if they are accurate predictors of morbidity and mortality; and if there is a substantive correlation between the two. Methodology: Conducted at the PICU of Hyderabad’s Lotus Children’s Hospital, the study population was restricted to children between the ages of 1 month and 18 years with the sample size being 100. To determine plasma lactate and base excess levels, venous blood was collected at the time of admission. Results: The mean lactate levels among the non survivors were significantly higher (mean: 52.45 +38.81 mg/dl) than the mean lactate levels among the survivors (mean: 21.86+ 8.25 mg/dl) and p < 0.01. There was also a significant correlation between elevated plasma lactate and days of hospital stay and ICU stay (p < 0.01).The mean venous base excess levels were more negative i.e., lesser among non survivors (mean: –16.86 + 8.25 meq/l) compared to survivors (mean: –9.91 + 5.62 meq/l) and p < 0.01. However, there was no statistically significant correlation between venous base excess levels and number of days of hospital stay (p= 0.025) and ICU stay (p = 0.15). Furthermore, there was an inverse correlation between plasma lactate and base excess levels with an increased morbidity and mortality rate with increasing trend in lactate or corresponding decreasing (more negative) base excess levels (p < 0.01). Conclusion: Hyperlactatemia and decreased venous base excess levels are significant predictors of outcome in critically ill children at presentation with initial plasma lactate being a better predictor in comparison to initial base excess levels