Weight reduction in non-insulin dependent diabetes mellitus (NIDDM) patients improves metabolic control, reduces cardiovascular risk factors, has blood pressure lowering effects and improves the well-being of the patient. This paper describes the role of very low calorie diets (VLCD), exercise, beta-adrenergic drugs and serotoninergic agents in the treatment of overweight in NIDDM. VLCD reduce body weight and improve glucose metabolism. Physical exercise programmes in addition to dietary restriction substantially contribute to weight loss and metabolic control in NIDDM. New specific beta-adrenergic agents, exhibiting virtually no beta 1 or beta 2 activity, increase energy expenditure and weight loss probably by enhancement of the basal metabolic rate. The target tissue in humans of this beta-adrenergic effect is as yet unknown. These drugs seem to enhance weight loss when used in combination with (very) low calorie diets compared to dietary restriction alone. Serotoninergic drugs reduce body weight by decreasing appetite, in particular for carbohydrates. Furthermore these drugs seem to improve insulin receptor sensitivity.