Urgent care is the elivery of a ambulatory care in a facility dedicated to the delivery of care outside of a hospital emergency department, usually on an unscheduled, walk-in basis. Urgent care centers are primarily used to treat patients who have an injury or illness that requires immediate care but is not serious enough to warrant a visit to an emergency room. Often urgent care centers are not open on a continuous basis, unlike a hospital emergency room that would be open at all times.