Metabolic complications of obesity. Obesity is associated with an increased risk of type 2 diabetes, cardiovascular disease, polycystic ovary syndrome and many other abnormalities. It is also central component of the so-called "metabolic syndrome". This article describes the most important metabolic complitacions of obesity, i.e. type 2 diabetes, dyslipidemia, growth hormone and sex hormones disturbances and also obesity-related cancer. It also underlines the role of insulin resistance as the main pathogenetic link between obesity and other above-mentioned conditions. Substances secreted by adipose tissue, which might impair insulin action and thus act as a mediators of insulin resistance, are described.