The coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a previously unrecognized viral illness with high infectivity that has sparked a global crisis. Poorly controlled diabetes was demonstrated to be a crucial risk factor for poor COVID-19 outcomes. COVID-19 infections are associated with severe metabolic dysfunctions, new-onset diabetes, and increased thrombotic events against the backdrop of aberrant endothelial function. The current body of evidence suggests that when hyperglycemia interacts with other risk factors, it might modify immune and inflammatory responses such that individuals become susceptible to severe COVID-19 infection and worse outcomes including higher mortality. Apart from their glucose-lowering actions, the pleiotropic effects of antidiabetic medications can inhibit viral action, attenuate endothelial dysfunction, ameliorate oxidant effects, and modulate inflammatory and immune responses during COVID-19 infections. These actions make antidiabetic medications feasible candidates for drug repurposing to combat the SARS-CoV-2-induced tsunami in diabetic COVID-19 patients. This review discusses the association between diabetes and COVID-19, pathophysiology of the disease in diabetes, and therapeutic potential of antidiabetic medications for diabetic patients during the current COVID-19 pandemic. Given the short history of human infection with SARS-CoV-2, the information provided by recent studies is limited. Hence, further investigations of the optimal management of patients with diabetes who are affected by COVID-19 are warranted. (J Intern Med Taiwan 2022; 33: 110-127)