Objectives: Diabetic individuals have a poorer prognosis when infected with COVID-19, a coronavirus disease. However, the impact of hyperglycemia on COVID-19 patients without a history of diabetes is not well understood. This study aimed to determine the prevalence of hyperglycemia and its effect on the prognosis of non-diabetic COVID-19 patients. Materials and Methods: A hospital-based cross-sectional study was conducted at the Jabra Isolation Centre in Sudan with 252 non-diabetic COVID-19 patients. The data collected included demographics, oxygen saturation, respiratory rate, ICU admission, length of hospital stay, and outcomes. The CURB-65(Confusion, Uremia, Respiratory rate, BP, age ≥ 65 years) pneumonia severity score was also evaluated for each participant. Blood glucose levels above 180 mg/dl were considered indicative of hyperglycemia. Results and Conclusion: A significant portion of non-diabetic COVID-19 patients exhibited hyperglycemia upon admission, which was strongly associated with a high CURB-65 score, severe COVID-19 infection, ICU admission, and a poor prognosis regarding length of hospital stay (LOHS) and mortality.