Bariatric surgery is effective on short- and medium-term weight loss, reduction of comorbidities, and overall mortality. A large and increasing portion of the population is eligible for bariatric surgery, which increases instant health care costs. A review of the literature identifies a series of ethical challenges: unjust distribution of bariatric surgery, autonomy and informed consent, classification of obesity and selecting assessment endpoints, prejudice among health professionals, intervention in people's life-world, and medicalization of appearance. Bariatric surgery is particularly interesting because it uses surgical methods to modify healthy organs, is not curative, but offers symptoms relief for a condition that it is considered to result from lack of self-control and is subject to significant prejudice. Taking the reviewed ethical issues into account is important when meeting persons eligible for bariatric surgery, as well as in the assessment of and decision making on surgery for obesity.