The Food and Drug Administration issued guidance for evaluating the cardiovascular risk of new diabetes mellitus drugs in 2008. Accumulating evidence from several completed trials conducted within this framework raises questions as to whether requiring safety outcome studies for all new diabetes mellitus therapies remains justified. Given the burden of cardiovascular disease in patients with diabetes, the focus should shift towards cardiovascular outcome studies designed to evaluate efficacy (i.e. to determine the efficacy of a drug over placebo or standard care) rather than demonstrating that risk is not increased by a pre-specified safety margin. All stakeholders are responsible for ensuring that new drug approvals occur under conditions of appropriate safety and effectiveness. It is also a shared responsibility to avoid unnecessary hurdles that may compromise access to useful drugs and threaten the sustainability of health systems. It is critical to renew this debate so that stakeholders can collectively determine the optimal approach for developing new drugs to treat type 2 diabetes mellitus.