Objective: To study the clinical and biochemical parameters that can predict cortisol insufficiency in children with septic shock. Design: prospective, observational study. Setting: tertiary health-care center. Patients/Subjects: Fifty children admitted with the catecholamine resistant septic shock to a tertiary health-care center. Materials and Methods: At the time of hospitalization all patients underwent detailed clinical evaluation including, history and physical examination, evaluation with the complete blood count, serum cortisol, renal function tests, liver function tests, prothrombin time activated partial thromboplastin time, arterial blood gas analysis, urine analysis, chest roentgenogram, ultrasonography of the abdomen and chest, urine, and blood culture for bacteria and fungi. Results: Out of 50 children with the catecholamine resistant septic shock, seven had adrenal insufficiency (serum cortisol <18 μg/dl). Of all parameters studied, only arterial bicarbonate at the time of admission to intensive care predicted adrenal insufficiency. On Receptor operative characteristic curve analysis, a bicarbonate level of 10.9 mEq/L had the best accuracy to predict adrenal insufficiency. Conclusion: Arterial bicarbonate may be used as a rapid test for provisional identification of adrenal insufficiency among children with the catecholamine resistant septic shock.