The severe coronavirus disease 2019 (COVID-19) is associated with increased levels of blood interleukin (IL)-6. Therefore, it is hypothesized that modulating the levels or effects of IL-6  could diminish airway inflammation and alter the course of COVID-19. We conducted a controlled, randomized, double-blind clinical trial on hospitalized patients with severe COVID-19 in Iran. The patients were randomly distributed by block randomization to take either standard-of-care (SOC) plus 1 or 2 doses of tocilizumab 8 mg/kg or SOC alone. The endpoint was defined by clinical improvement and discharge. We enrolled 40 patients (20 patients in each group) from 10 July to 10 December 2020. After randomization, 1 patient in the SOC arm and 3 patients in the tocilizumab arm refused to participate and were eliminated from the study. The mean age of participants was 59.62±15.80 in the tocilizumab group (8 women and 9 men) and 63.52±12.83 years old in the SOC group (9 women and 10 men) groups. The number of patients who recovered did not differ significantly between the tocilizumab and SOC groups (12 [70.6%][70.6%] vs. 15 [78.9%]), respectively). Hospitalization rates were also similar between the groups (Log-rank test, p=0.615; hazard ratio, 0.83; 95% C‎‎I [0.‎39-1.78]). The results show that tocilizumab could not be a beneficial agent for treating severe cases of COVID-19 patients and would not significantly improve clinical outcomes.