Over the last 30 years overweight and obesity among adults and children have been on the rise, and since 1997 WHO has designated obesity as a major public health problem. In Greece both adult and childhood obesity is now recognized as an epidemic problem, probably more important than in other European countries. The issue is more serious in male adolescents and adults. There is also a tendency for weight increase along the last 30 years. Metabolic syndrome and type 2 diabetes mellitus are also rising rapidly in the Greek population. The reasons for this epidemic in Greece are not clear. Possible explanations could emerge from the delayed but sharp economic evolution of the country, as well as the abandonment of the traditional Mediterranean diet. Other predisposing factors in Greek children are parental obesity, frequent television viewing, low rates of breastfeeding and, in adolescent girls, smoking and alcohol consumption. Emerging measures are needed to confront this epidemic.