Many of the pediatric inpatients you care for will need intravenous fluids and electrolytes. This episode describes what you need to know before you order fluids or electrolyte replacement for your patient. We will discuss maintenance fluid needs and talk more in depth about what fluids to order and at what rate. We will also talk about managing patients with dehydration and how to replete fluids. Then we will discuss a few cases where we will work through some more common electrolyte derangements and discuss how to manage them. We will end with additional clinical pearls that will be helpful during your time on the inpatient pediatric service. Introduction Definition of maintenance fluid needs Important considerations about maintenance fluids Discussion regarding which fluids to order for different patient populations and at what rate to administer Role of ADH in hospitalized patients How to order a fluid bolus—amount, composition, and rate administered Assessing your patient with dehydration utilizing physical exam findings, vital signs, and other objective data such as weight Case scenarios: Identification and management of hyperkalemia and hypokalemia Case #1- 12-year old with hyperkalemia following infection with influenza Case #2- 2-year old child with history of neglect and malnutrition Additional clinical pearls including the association between albumin and calcium, acidosis/alkalosis and potassium levels Resources/Links:  Clinical Practice Guideline: Maintenance Intravenous Fluids in Children | Pediatrics | American Academy of Pediatrics (aap.org)