Anesthesiology is the medical specialty that provides anesthesia during surgery and other invasive procedures, in critical care, and in management of acute and chronic pain. Through its core expertise of keeping patients safe and comfortable during invasive or painful procedures, anesthesiology enables the activities of every surgical discipline and an increasing percentage of nonsurgical specialties as well, including complex cardiac catheter-driven procedures. Anaesthetists have always been leaders in patient safety, perhaps because of the immediacy that an error can bring. Hospital care is still hazardous for patients, but anaesthesia for the American Society of Anesthesiologists [ASA] physical status I and II patients undergoing day case surgery is one of the safest and reliable procedures that a patient can have. The aim of this work was to present a practical framework for developing and implementing QI programs in anesthesiology and critical care medicine that are both scientifically sound and feasible. To accomplish this goal, we review the science and approaches to QI, present measures that help evaluate whether QI programs have resulted in improvements, and describe examples of successful QI efforts.