Obesity is a chronic endocrine-metabolic disease with a multifactorial etiology and a polygenetic basis, whose complex patophysiologic mechanism causes numerous complications. Fat tissue is a gland which "communicates" intensively with the whole organism. It secretes adipokines which have an endocrine, paracrine and autocrine function. In obesity, adipokine synthesis, secretion into the blood and effect on the target tissues and organs is impaired, leading to development of complications in all organic systems. Pandemic levels of obesity and overweight are such that both in developed and developing countries only a small part of the population has normal body weight. In Croatia every fifth adult is obese, and overall 2/3 of men and little more than 1/2 of women have body weight greater than normal. Mortality rises with BMI >25 kg/m2 and in obese persons it is 1.5-2 times greater, while in persons with morbid obesity (BMI >40 kg/m2) the life expectancy is 5-15 years shorter. Treatment of obesity is a long-term endeavor and requires the participation of physicians of various specialties. The Croatian Obesity Society held the 3d Croatian Congress on Obesity with international participation in Opatija from 4-6 April. The main topics of discussion were obesity epidemiology and diagnostics, patophysiologic mechanisms, complications, mortality and disease treatment. The National Programe for Countering the Obesity Epidemic was presented. At the end of the Congress the 3d National Consensus on Diagnostics and Treatment of Obesity was adopted. It incorporated some changes compared to the previous 2006 Consensus. The new obesity treatment guidelines take individual needs and capabilities more into account, with the aim of increasing the success of the treatment.