Background: Management of Coronavirus disease 2019 (COVID-19) patients with underlying disorders is a challenging issue at any time. Objectives: The present survey investigated the mortality rate of COVID-19 patients with various underlying disorders. Methods: In the present cross-sectional study, patients with COVID-19 who were referred to the Razi Hospital in Ahvaz from Feb 2020 to Oct 2020 were evaluated. Non-probability sampling method was used for sample collection. All documented information, including length of hospitalization, comorbidities, survival, and clinical and laboratory findings, were collected. Results: In the present study, 500 diabetic patients with COVID-19 infection were included. The mean age of participants was 59.61 ± 14.88 years old. Of the subjects, 192 (38.4%) were female and 308 (61.6%) were male. DM solely was the most frequent underlying disorder (46.2%), followed by co-occurrence of DM and hypertension (HTN) (43%). The mortality rate was 15% and was more frequent in patients with simultaneous DM and HTN (66%) (P-value < 0.001). Also, the mortality rate was significantly higher in males than females (72% vs 28%) (P-value = 0.042). Further analysis indicated that the mean of white blood cells (WBC), neutrophil count, blood urea nitrogen, glucose, creatinine, and aspartate aminotransferase were significantly higher in expired patients (P-value < 0.05). Post Hoc analysis showed the highest pulse rate (PR) and respiratory rate (RR) in patients with DM, HTN, and chronic obstructive pulmonary disease (COPD) (P-value < 0.001). Conclusions: The present investigation showed that comorbidities significantly increase the COVID-19 mortality rate. Our findings revealed that more attention is required for COVID-19 patients with HTN and DM. Due to discrepancies with recent investigations, further studies with more follow-up are recommended.