Abstract: This monograph addresses the most common medical conditions that may result in significant surgical morbidity and mortality. Coexisting cardiovascular, pulmonary, hematologic, and endocrine diseases must be recognized preoperatively. Recognition of risk factors, proper evaluation and testing, and appropriate referral to medical specialists for recommendations regarding preoperative preparation and perioperative care are important for a successful outcome. The use of complementary and alternative medicines is an increasing practice for many patients and warrants attention by the gynecologic surgeon because surgical complications may result from the inappropriate use of these medicines preoperatively. Special circumstances such as pregnancy, advanced age, and morbid obesity must be taken into consideration in preoperative evaluation because these conditions may result in complications even if the patient appears to be healthy.