Our retrospective study aimed to evaluate the effectiveness of monoclonal antibodies (casirivimab and imdevimab) on mild cases of coronavirus disease 2019 patients admitted to the tertiary care center. A total of 161 patients were evaluated of which the test group consisted of 79 and the control group of 82. In the test group the patients had been administered with diluted 250 ml of 0.9 % sodium chloride along with co-formulated casirivimab (600 mg) and imdevimab (600 mg) solution intravenously and in the control group the patients were administered standard coronavirus disease 2019 treatment protocol. The monitoring of patients in both groups was done at least 1 h after drug infusion in the designated room. Post-treatment designed interviews were taken to evaluate the effectiveness of treatment. This retrospective analysis discovered a significant association of symptoms with the group at 48 h for injected and non-injected patients and 1 mo from the chi-square test after injecting monoclonal antibodies. There is no significant association of symptoms with the groups at 3 mo. A significant difference in the symptom distribution through different time points in the injected group and not injected group was observed. From the pairwise McNemar's test, a significant difference in the symptoms between each time in 48 h, the difference was p=0.0075 and after 1 mo, p<0.001 points in both groups. The combination of casirivimab and imdevimab could be considered a treatment of choice for vaccinated, non-vaccinated and mild to highrisk coronavirus disease 2019 patients.