Abdominal obesity is a risk factor for cardiovascular disease worldwide, and it is becoming a dramatic issue for national health systems. Overweight and obesity are highly associated with multiple comorbidities, elevated blood pressure values, dyslipidaemia, reduced insulin sensitivity and alterations of large and minor vessels. Activation of the renin-angiotensin system (RAS) in adipose tissue may represent an important link between obesity and hypertension. Angiotensin II has been shown to play a role in adipocyte growth and differentiation. Adipocytes also secrete adiponectin, enhancing insulin sensitivity and preventing atherosclerosis. Blockade of the RAS with either an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker results in a substantial increase in adiponectin levels and improved insulin sensitivity. Obesity-related hypertension needs a comprehensive approach to treatment including both weight loss and pharmacological therapies. Antihypertensive drugs prescription should be based on guidelines recommendations for management of hypertension, taking into account the growing evidences about the relationship between some antihypertensive drugs and the development of new-onset diabetes. This review discusses the role of RAS in the relationship between obesity, essential hypertension and insulin resistance.