EMPA-REG OUTCOME was a multicenter, randomized placebo-controlled trial that examined the effect of empagliflozin, a sodium–glucose cotransporter 2 (SGLT2) inhibitor in addition to standard of care in patients with type 2 diabetes and established cardiovascular (CV) disease. The primary goal was to assess CV safety, as mandated by the US Food and Drug Administration since 2008 for all new glucose-lowering agents. Secondary goals were to examine the effects of empagliflozin on microvascular outcomes and, in particular, kidney disease. This landmark study had several important findings, including striking reductions in the incidence of CV death and heart failure hospitalization and in the progression of renal dysfunction. In this review, we describe the trial’s main findings, discuss the possible mechanisms that could explain its results, suggest ways in which clinical care may be influenced, and propose directions for future research.