Introduction: COVID-19, in combination with steroid treatment, is known to propagate hyperglycemia in diabetic patients. The purpose of this study was to establish a new insulin protocol for diabetic patients with COVID-19 on the dexamethasone protocol for better glycemic control. Research Design and Methods: This was a retrospective cohort study conducted at NYU Langone Long Island Hospital from 1 July 2020 to 1 July 2021. Eligible cases had to meet the following inclusion criteria: age of 18 years or greater, history of or new-onset diabetes, diagnosis of COVID-19 and receiving the 10 day dexamethasone treatment, length of stay of at least 3 days with a minimum of 48 h of glucose monitoring, and requiring basal and prandial insulin with correction during hospital stay. Data were collected using the hospital’s electronic record system. The total basal, prandial, and daily doses of insulin on the day at which glycemic control was achieved, or if glycemic control was not achieved by the discharge date, then on the completion date of the dexamethasone treatment, were collected and assessed. Results: A total of 145 patient cases were analyzed. About 46% of patients achieved glycemic control. The average insulin dose required was 0.67 (0.61–0.74) unit/kg. The mean total dose of insulin was 59 units. The mean total basal dose was 21 units. The mean total prandial dose was 38 units. The average prandial doses were higher than the basal doses for all participants. Conclusions: Diabetic patients with COVID-19 on dexamethasone should be initiated on at least 0.6–0.7 u/kg of insulin to achieve glycemic control.