Background: Elderly people are particularly affected by COVID -19. Elderly people who suffered from other diseases and were frail were particularly likely to develop severe COVID -19 or die from the infection. The aim of the current study is to assess the frailty index in COVID -19 geriatric patients admitted to hospital using the Clinical Frailty Scale and the FI -Lab21 and to establish a relationship between frailty and outcome prediction. Methods: In a prospective observational study we conducted, we assessed the clinical presentation and frailty-related characteristics of hospitalised individuals aged > 65 years with positive moderate-severe COVID -19 pneumonia. The Clinical Frailty Scale (CFS) and FI Lab-21 criteria were used to assess frailty at the time of admission. Mortality and change in CFS score from admission to discharge were recorded. Results: The age of patients participating in the study COVID -19 ranged from 65 to 90 years, and the mean age was 72.14±6.13 years. Men predominated in the study population (73.0%). Using the Clinical Frailty Scale (CFS), 21.0% of patients were not frail (score 1-3), 46.0% were mildly to moderately frail (score 5-6), and 33.0% were severely frail (score 7-8). Among the frail patients, the severely frail cases (based on CFS) were significantly older than the mild-to-moderate and nonfrail COVID -19 cases. The mortality rate was significantly higher in severely frail (66.7%) and mild-to-moderately frail (45.7%) patients than in nonfrail (28.6%) patients. Conclusion: The results show that the clinical frailty scale has no significant association with FILab-21 in COVID -19 cases. CFS showed a significant association with disease progression in COVID -19 cases.