Obesity, that is, having a body mass index (BMI) >30 kg/m², has increased dramatically and became the most single most common preventable cause of death in South Korea. In the end, obesity results in metabolic syndrome, which includes abdominal obesity, increased triglycerides, decreased high-density lipoprotein, hypertension, and impaired glucose tolerance. Nonsurgical methods for obesity treatments include dietary therapy, exercise counseling, behavioral therapy, psychiatric therapy, and pharmacotherapy. Surgical methods for obesity treatments, laparoscopic gastric banding and Roux-en-Y gastric bypass, are commonly performed for obese patients, particularly those with a BMI of 40 kg/m² or at BMI more than 30 kg/m² with accompanying diseases related to metabolic syndrome such as hypertension, type 2 diabetes, hypercholesterolemia, asthma, angina, other cardiopulmonary diseases, infertility, polycystic ovary, urinary incontinence, severe arthritis, or Pickwickian syndrome. Preoperative evaluation for bariatric surgery should focus on airway management, sleep apnea history, use of a continuous positive airway pressure device, and comorbid systemic diseases. Special consideration and pharmacokinetic knowledge is needed for the choice and dose of the anesthetic agents as well as postoperative pain control, patient monitoring, fluid intake, and surgical complications. Obesity is a disease. Appropriate surgical intervention and peri-operative anesthetic care for bariatric surgery will increase the safety and satisfaction of obese patients and will finally provide a better quality of life for our society.