Introduction: Diabetes mellitus has been perceived as the worsening factor for coronavirus disease 2019 (COVID-19), where diabetes mellitus patients with pre-existing inflammatory condition could develop acute respiratory disease syndrome as well as multi-organ dysfunction. Managing diabetes mellitus amidst severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is also a matter of concern as several antidiabetic therapies could affect the progression of COVID-19. This study aimed to provide the clinical characteristics and outcomes of patients with both COVID-19 and diabetes mellitus receiving blood glucose lowering therapies and COVID-19 symptomatic treatments. Methods: This retrospective study was performed on 260 medical records of patients hospitalized between May 2020 to February 2021 in East Java, Indonesia. Patients were confirmed COVID-19 positive based on the results from real time polymerase chain reaction (RT-PCR) using nasal swab samples collected on hospital admission. Data included were demographic characteristics, COVID-19 symptoms, severity of COVID-19, comorbidities (other than diabetes mellitus), fasting blood glucose (FBG), and 2-hours post-prandial blood glucose (2hPBG), and outcomes. Results: Most of the patients had age range of 41–60 years old (76.1%) with more than a half of the subjects (60%) were obese. Patients with uncontrolled diabetes were distributed evenly among the COVID-19 severities (74.3% in asymptomatic group, 73.6% in mild group, and 74.1% in moderate group). There were reductions in FBG and 2hPBG levels measured before (210.75±81.38 and 271.19±100.7 mg/dL, respectively) and after the treatment (181.03±68.9 and 222.01±86.96 mg/dL, respectively). All patients received multivitamin and symptomatic treatment for COVID-19. Oral antidiabetic drug (57.6%) and insulin (28.8%) were administered to lower the blood glucose level of the patients. As many as 96.9% patients survived, while 3.1% died. Conclusion: COVID-19 could affect the blood glucose level, suggesting the importance of antihyperglycemic therapies among patients with both COVID-19 and diabetes mellitus.