Two types of endocrine problems are seen in pediatric critical care: specific endocrine abnormalities (diabetes mellitus, panhypopituitarism) and endocrine dysfunction secondary to critical illness (sick euthyroid or syndrome of inappropriate antidiuretic hormone [SIADH]). This chapter provides a brief description of the developmental anatomy and physiology of the endocrine system. It discusses the clinical assessment of endocrine function. The chapter describes endocrine disorders such as critical illness-related corticosteroid insufficiency, diabetes mellitus, hyperglycemic hyperosmolar syndrome, acute hypoglycemia, SIADH, diabetes insipidus, and cerebral salt wasting. Endocrine disorders in pediatric critical care can be difficult to diagnose and treat. They can have profound effects and are often confused with other disorders. Providers must be diligent in directing their care and pay great attention to detail in the management of these children. Prompt treatment of endocrine disorders return critically ill children to their baseline function and can prevent untoward debilitations in long-term health.