This chapter discusses a major medical procedure called preanesthetic evaluation. Maximum operative procedures require preanesthetic assessment — also called preanesthesia evaluation, preanesthetic checkup (PAC) or simply preanesthesia — which includes thorough medical checkup and laboratory investigations done by the anesthesiologist before an operation, to assess the patient\'s physical condition and any other medical problems or diseases the patient might be suffering from. For an elective surgery, preoperative check-up should be performed as soon as the patient is planned for operation. This will provide sufficient time to the anesthesiologist to order any further investigations if necessary. While taking history, the examiner should elicit details about the present illness and other associated illnesses that the patient may be having. The other assessment areas include the cardiovascular system, the respiratory system, respiratory system and the nervous system. Radiological Assessment and Hemoglobin, Hematocrit and Complete Blood Count tests are also required before applying anesthetics on a patient. To assess perioperative risk, several complicated classification systems are available. The American College of Cardiology (ACC) and the American Heart Association (AHA) have published guidelines for perioperative cardiovascular evaluation and clinical predictors of increased perioperative cardiovascular risk for myocardial infarction, congestive heart failure and death.