The pandemic of the novel human coronavirus disease 2019 (COVID‐19) has become an evolving global health issue due to the high morbidity and mortality rate. Patients who have comorbidities (e.g., diabetes, hypertension, obesity, cancer, and cardiovascular disease) are significantly at increased risk for admission into the intensive care unit, and this situation could affect the survival of the infected patients. Among the various comorbidities in this review, we focused on the diabetic patients who were highly affected because of increased viral entry into the cell via angiotensin-converting enzyme 2 (ACE2) in the respiratory system, leading to decreased immunity. Furthermore, several studies have been conducted on the beneficial effects of metformin in diabetic patients with COVID-19, but other studies have demonstrated the severe course of COVID-19 disease. Hence, further comprehensive studies are necessary in this regard. For these reasons, the prevention and management of COVID-19 in diabetic patients are essential and play a key role in reducing the fatality rate.