Obesity is a significant medical, social and economic problem. A trend of increasing prevalence of obesity is observed in many countries, including Poland. Obesity, as a serious disorder, leads not only to socioeconomic, but also many important medical consequences. The treatment of morbid obesity includes conservative (pharmacological and non-pharmacological) and invasive (usually surgical) procedures. Surgical methods performed for the treatment of morbid obesity include restrictive and malabsorptive procedures. All of them lead to significant long-term body mass loss. In this article the authors discuss the problem of whether morbid obesity should be treated conservatively or surgically.