Aim: To evaluate the influence of diabetes on the severity and fatality of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Materials and Methods: The medical records of 66 hospitalized coronavirus disease 2019 (COVID-19) patients were collected and classified into non-severe (mild/moderate cases) and severe (severe/critical cases) groups. Logistic regression analysis was used to estimate the risk of severe COVID-19 (severe/critical infection). In addition, a meta-analysis including published studies reported the impact of diabetes on the severity and fatality of COVID-19. The current study was conducted using fixed effects models. Results: There were 22 diabetes and 44 non-diabetes cases among the 66 hospitalized COVID-19 patients. Seven patients with diabetes (31.82%) were diagnosed as severe COVID-19 cases, which was significantly higher than that in the non-diabetes group (4/44, 9.09%, P = .033). After adjustment for age and gender, diabetes was significantly associated with COVID-19 severity (OR: 5.29, 95% CI: 1.07–26.02). A meta-analysis further confirmed the positive association between diabetes and COVID-19 severity (pooled OR = 2.58, 95% CI: 1.93–3.45). Moreover, the patients with diabetes infected with SARS-CoV-2 had a 2.95-fold higher risk of fatality compared with those patients without diabetes (95% CI: 1.93–4.53). Conclusions: Our findings provide new evidence that diabetes is associated with a higher risk of severity and fatality of COVID-19. Therefore, intensive monitoring and antidiabetic therapy should be considered in patients with diabetes with SARS-CoV- 2 infection.