Preoperative assessment and preparation of the patient is an indispensable part of every surgical procedure. Personal anamnesis provides information about medical history, previous surgical procedures and experiences with general anesthesia, current illness, allergies, specific information such as increased tendency to bleed, difficulty opening the mouth or swallowing, night snoring, and information about medications that the patient is currently taking. The physical examination is especially focused on the examination of the cardiovascular and respiratory systems and the assessment of the respiratory tract. As part of the pre-operative preparation, it is necessary to assess the patient's cardiac function and functional status, cardiovascular risk and the risk of surgery. Mandatory laboratory diagnostics include a complete blood count, standard coagulation tests, serum electrolyte and glucose values, pre-transfusion testing, and assessment of renal function. Very common comorbidities in cardiac surgery patients are anemia, preoperative hyperglycemia, and renal insufficiency, and they need to be treated preoperatively. Radiography of the chest organs is necessary in all cardiac surgery patients, especially those in whom an operation that includes a sternotomy is planned. As part of the preoperative administration of drugs, therapy with certain groups of drugs should be discontinued, gastroprotective drugs may be used, antimicrobial prophylaxis and analgetics should be used, and if necessary, anxiolytics. Given the specifics of the cardiopulmonary bypass operation, in patients scheduled for a surgical procedure that includes a bypass, it is necessary to maintain specific hemodynamic goals preoperatively, which is achieved by restricting intravenous fluid intake and using medications.