Background: Non-invasive ventilation (NIV) is recognized as a practical and effective method for assisting selected patients with respiratory issues. The HACOR scoring system evaluates heart rate, acidosis, consciousness, oxygenation, and respiratory rate and has proven to be predictive of NIV failure in critically ill patients like COVID-19 patients. Aim: To determine the predictability of HACOR score to identify NIV failure early in patients with respiratory failure linked to COVID-19. Methods: This cross-sectional study was carried out at the ICU of Bangabandhu Sheikh Mujib Medical University (BSMMU) and Dhaka Medical College Hospital over a one-year period. It involved 40 patients who were administered NIV via a conventional ventilator in spontaneous mode and selected based on specific inclusion and exclusion criteria. Informed written consent was obtained from each patient’s guardians. Upon admission to the ICU, the HACOR score of each patient was measured after one hour of NIV treatment, assessing factors such as heart rate, pH levels for acidosis, and oxygenation through the PaO2/FiO2 ratio, along with respiratory rate. Analysis was performed with both manual methods and software SPSS version 24. Results: NIV failure occurred in 33 (82.5%) patients with only 7 (17.5%) achieving successful NIV. Older patients experienced NIV failure significantly higher compared to those with successful outcomes (average ages 61.79±17.28 vs. 47.57±11.92 years, p=0.045), and male patients were predominant (66.66%). The predominating comorbidities were diabetes mellitus (57.5%). The HACOR scores were significantly higher in patients who failed NIV compared to those who succeeded (8.18±2.18 vs. 4.71±1.5, p=0.002). Receiver operating characteristic (ROC) curve analysis established a HACOR score cutoff value of 5 after one hour of NIV treatment for predicting NIV failure in the study population, demonstrating a sensitivity of 93.9% and a specificity of 57.1% (AUC: 0.905). Conclusion: Despite the study's limited sample size, findings suggest that the HACOR score may serve as an early indicator of NIV failure in critically ill patients with COVID-19-related respiratory failure. Future research on a larger scale is anticipated to validate and expand upon these important insights.