Emergency Nursing is a nursing specialty in which nurses care for patients in the emergency or critical phase of their illness or injury.

In contrast to practically every other specialty of nursing, in which a patient arrives with a diagnosis applied by a physician and the nurse must manage the patient's care according to that diagnosis, emergency nurses work with patients in whom a diagnosis has not yet been made and the cause of the problem is not known. Emergency nurses frequently contact patients in the emergency department before the patient sees a physician. In this situation, the nurse must be skilled at rapid, accurate physical examination, early recognition of life-threatening illness or injury, the use of advanced monitoring and treatment equipment, and in some cases, the ordering of testing and medication according to "advance treatment guidelines" or "standing orders" set out by the hospital's emergency physician staff. As any type of patient from newborn to elderly, from minor injury to critical trauma or illness may present to the emergency department, emergency nursing encompasses aspects of pediatrics, obstetrics, critical care, psychology and geriatrics. Emergency nursing may also involve aspects of law enforcement, as in the care of assault or rape victims, or those involved in drunk driving or drug abuse; in these cases, the nurse must care for the patient while simultaneously preserving and collecting evidence for future legal use.