The American Society of Anesthesiologisth Physical Status (ASA PS) scale is one of the most widely used scales in the world, being an integral part of the pre-anesthetic evaluation of each patient. The purpose of the ASA PS scale is to categorize, and subsequently communicate the patient’s risk of undergoing any procedure that requires anesthesia. The objective of this article is to review the classification and incorporate examples, associating them with perioperative risk, in order to improve categorization and clinical practice in our setting.