Abstract Background: To access the effect of Intravenous immunoglobulin ‎‎(IVIG) in critically ill corona virus disease 2019 (COVID-19) patients. Method: In this retrospective matched cohort study, records of three tertiary centers with large number of COVID-19 admissions were evaluated and used. Based on treatment options, ‎patients were divided into two groups, standard COVID-19 treatment (109 patients) and IVIG treatment (74 patients) patients. Also, the effect of IVIG in different dosages was evaluated. Patients with IVIG treatment were divided into three groups of ‎low (0.25 gr/kg), medium (0.5 gr/kg), and high (1 gr/kg) dose. Data analysis was performed using independent t-test and ‎One-way analysis of variance (ANOVA) to compare the ‎outcomes between two groups, including duration of hospitalization, intensive care unit (ICU) length of stay, and mortality rate.‎ Result: The duration of hospitalization in the IVIG group ‎were significantly longer than standard treatment (13.74 days vs. 11.10 days, p<0.05). There was not a significant difference between the two groups in ICU length of stay, number of intubated patients and duration of mechanical ventilation (P>0.05).‎ Also initial ‎outcomes in IVIG subgroups were compared separately with the standard ‎treatment group. The results indicated that only the duration of hospitalization ‎in the IVIG subgroup with medium dose is significantly longer than the standard ‎treatment group (P<0.01). Conclusion: Using IVIG is not beneficial for COVID-19 patients based on no remarkable differences in duration of hospitalization, ICU length of stay, duration of mechanical ventilation and even mortality rate.