Objective: The current study aims to determine the frequency of diabetes mellitus in patients with COVID-19 infection. Methodology: Our cross-sectional study was conducted on 120 patients who presented with COVID-19 to Dr. Ziauddin Hospital, North Nazimabad, Karachi, from December 2021 to May 2022. The frequency of diabetes in these patients was determined. Results: In this study, the mean age of the patients recorded was 53.72±10.42 years. Frequency of diabetes was 37 (30.8%). Diabetes was significantly associated with hypertension, ischemic heart disease, and chronic kidney disease. Conclusion: The frequency of diabetes in COVID-19 patients in our study was 37 (30.8%). Diabetes was significantly more common in patients with comorbidities such as hypertension, ischemic heart disease, and chronic kidney disease. We recommend proper management of diabetic patients with COVID-19 infection as it can lead to a fatal manifestation of the disease.