The use of ketamine for pediatric sedation in the Emergency Department for painful procedures has become increasingly popular. Ketamine is a safe and effective sedative for diagnostic or therapeutic procedures in the Emergency Department. Sedation with this dissociative agent produces a rapid onset action, potent analgesia, adequate sedation, amnesia and minimal side effects. We report a case of prolonged sedation and airway complications after administration of an inadvertent intramuscular ketamine overdose in a healthy child.