Background: The rate of mortality from septic shock currently remains high in pediatric intensive care units. In this disease, adrenal insufficiency is a commonly occurring problem that also influences prognosis. Diagnosis and treatment are still controversial. In consideration of these issues, we determined the rate of adrenal insufficiency in children suffering from the condition and the role of blood cortisol levels in prognosis. Materials and Methods: This prospective, descriptive, analytical study involved 74 septic shock cases at the intensive care unit and emergency department of Children’s Hospital 1 in Vietnam. The research was conducted from October 2008 to April 2011. Results: Most of the subjects were under 5 years old (81.5%), and 46.8% of them were male. Malnutrition occurred in 14.9% of the patients. The majority were in very serious condition upon admission, all were in decompensated shock, 55.4% had unmeasured blood pressure, 73% were afflicted with disorders of consciousness accompanied by confusion and coma, 46.8% needed to be intubated at admission, and 94.6% exhibited multiorgan dysfunction. The PRISM II of the children averaged at 26.6±10. Adrenal insufficiency rates were 9.5%, 13.5%, and 31.1% at admission, at 6 hours after treatment, and at the 24th hour of intervention, respectively. Such rate was 41.9% overall. Adrenal insufficiency was unrelated to mortality, but the group with blood cortisol levels >340 ng/mL had a higher mortality rate. Among the children, 86.3% had blood cortisol levels >180 ng/mL, and 16.1% children had blood cortisol concentrations <180 ng/mL (p = 0.018)-both suffered additionally from disorders involving three or more organs. Blood cortisol concentrations gradually decreased over three times at certain points in the research. No difference in time and number of vasoactive drugs was found between the groups of patients with and without adrenal insufficiency. The former had higher dopamine concentrations in the body (p = 0.028). Conclusion: The majority of the children were in very serious condition and suffered from decompensated shock, with many of their organs affected. The rate of adrenal insufficiency in the sample was high but unassociated with mortality. Blood cortisol increased at the time of diagnosis and decreased after. The children with adrenal insufficiency had higher levels of dopamine in their system.