The clinical characteristics of and outcome for 75 children with meningococcal septic shock were studied. In addition, a new prognostic scoring system was developed. The median age of the patients was 3.2 years (range, 3 weeks to 17.9 years). The most common phenotype of Neisseria meningitidis was B:4:P1.4 (27%). A mortality rate of 21% was observed. Ten (17%) of the 59 survivors had serious sequelae. Calcium levels were significantly lower in patients with seizures. Disseminated intravascular coagulation occurred in 58% of the patients who were tested. Logistic regression analysis identified four laboratory features independently associated with mortality: serum C-reactive protein level, base excess, serum potassium level, and platelet count. These features were used to develop a novel scoring system with a predictive value for death and survival of 71% and 90%, respectively. The outcome was predicted correctly for 86% of the patients, which is higher than rates previously reported for scoring systems.