Diabetes is one of the most commonly reported comorbidities in COVID-19-infected patients. According to current data, diabetic patients do not appear to be at increased risk of contracting SARS-CoV-2 compared to the general population. However, diabetes is a risk factor for developing severe and critical COVID-19 forms, which often require intensive care unit admission and, eventually, invasive mechanical ventilation, which are associated with high mortality rates. The characteristics of COVID-19 diabetic patients and prognostic impact of diabetes on SARS-CoV-2 infection are currently under investigation. Obesity, the main risk factor for incident Type 2 diabetes, appears to be more common in patients with critical COVID-19 forms that require mechanical invasive ventilation. In diabetic patients, COVID-19 is associated with poor glycemic control and acute metabolic complications like ketoacidosis. At present, there are no recommendations in favor of discontinuing antihypertensive medications that interact with the renin-angiotensin-aldosterone system. Owing to the risks of lactic acidosis and ketoacidosis, metformin and SGLT2 inhibitors should be discontinued in patients with severe COVID-19 forms. Finally, we advise a systematic screening for (pre)diabetes in patients with proven SARS-CoV-2 infection.