Three contrasting cases of obese patients with type 2 diabetes mellitus are presented, which illustrate the management difficulties faced by clinicians. The first raises the issue of when to commence an oral hypoglycaemic agent in a newly diagnosed but asymptomatic obese patient; the second case addresses the problem of when to commence insulin in the face of continuing weight gain and poor glycaemic control; the final case is an example of the vicious metabolic spiral which so many patients enter, with increasing body weight, poor diabetic control and associated co-morbidities. The discussion that follows each case presentation recognises the considerable cardiovascular risk faced by such patients and provides guidance about possible management pathways including adjunctive anti-obesity pharmacotherapy.