Cardiorespiratory fitness is inversely related to the development of type 2 diabetes and cardiovascular morbidity and mortality. Trials in individuals with impaired glucose tolerance have highlighted the role of physical activity/exercise in the prevention of type 2 diabetes. Moreover, physical activity and exercise training have been recognized as treatment options for patients with type 2 diabetes. Both aerobic and resistance training were shown to produce beneficial effects by reducing HbA(1c), inducing weight loss and improving fat distribution, lipid profile and blood pressure in patients with type 2 diabetes. Mixed aerobic and resistance training was recently shown to be more effective than either one alone in ameliorating HbA(1c). However, further research is needed to establish the volume, intensity and type of exercise that are required to reduce cardiovascular burden and particularly to define the best strategy for promoting long-term compliance and durable lifestyle changes in individuals with type 2 diabetes. The Italian Diabetes Exercise Study (IDES) is a prospective Italian multicentre randomized controlled trial, of larger size and longer duration than previously published trials. It has been designed to assess the combined effect of structured counselling and supervised mixed (aerobic plus resistance) exercise training, as compared with counselling alone, on HbA(1c) and other cardiovascular risk factors as well as fitness parameters in individuals with type 2 diabetes and the metabolic syndrome. This study was also aimed at testing a sustainable strategy for promoting and maintaining a sufficient level of physical activity among individuals with type 2 diabetes to be implemented at the population level.