This Forum addresses the role of mitochondrial dysfunction in the multifactorial nature of diabetic cardiomyopathy (DCM) from multiple angles. Contributors deliver a diverse and in-depth view of the state-of-the-art in DCM, from bench to bedside. What emerges is a picture of mitochondrial dysfunction as a central upstream defect, inflicted on the heart by diabetes. Collectively, the authors pinpoint high-value knowledge gaps, propose new conceptual frameworks, and highlight understudied, but promising, research themes.