Recent major clinical trials of the use of sodium-glucose cotransporter 2 (SGLT2) inhibitors in patients with type 2 diabetes have shown that they reduce three-point major adverse cardiovascular events, cardiovascular death, hospitalization for heart failure (HF), and a composite renal outcome. These beneficial effects of SGLT2 inhibitors are also evident in type 2 diabetic patients with a previous history of atherosclerotic cardiovascular disease or advanced renal disease. HF is a major determinant of the prognosis of diabetic patients. Although HF with low ejection fraction (HFrEF) can be effectively treated with antihypertensive drugs, these treatments do not reduce mortality in HF patients with preserved ejection fraction (HFpEF). HFpEF is clinically characterized by preserved left ventricular distention, perivascular fibrosis, and stiffness of cardiomyocytes, defined as “cardiomyopathy”. Therefore, HFpEF is considered to be an entirely separate entity to HFrEF. Recent studies have suggested that HFpEF may be treatable using SGLT2 inhibitors, which ameliorate visceral adiposity, insulin resistance, hyperglycemia, hyperlipidemia, volume overload, hypertension, and cardiac inflammation. In the final part of the present review, we discuss the biochemical and molecular mechanisms of the effects of SGLT2 inhibitors in type 2 diabetes patients with HFpEF. These involve amelioration of the low nitric oxide production and oxidative stress, a reduction in cardiac inflammatory cytokine signaling, inhibition of Ca overload, and an improvement in cardiac energy metabolism due to ketone body production. Investigations of the beneficial effects of SGLT2 inhibitors on cardiorenal outcomes, including hospitalization for HF, are now being conducted in pre-clinical and clinical studies.This article is protected by copyright. All rights reserved.