Recently, Leahy et al. issued a "consensus statement" in regard to targeting β-cell function in therapy for type 2 diabetes that recommends continued multidisciplinary efforts to realign treatment of type 2 diabetes to preserve β-cell function by early intervention. This might be applicable not only for obese type 2 diabetes in Europe and America, but also for lean type 2 diabetes in Asia. To establish evidence, development of non-invasive measurements of β-cell mass for longitudinal observation during long duration of diabetes is critical. In addition, studies that clarify the development of β-cell dysfunction with regard to both mass reduction and functional impairment are required for the development of novel strategies to preserve β-cell function by treatment of type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00117.x, 2011).