Introduction: The superiority of favipiravir which is one of the agents used in the treatment of COVID-19, over other treatments is still controversial. With this study, we aimed to show whether there is a difference between the initial or subsequent addition of the drug to the treatment on the treatment success and 28-day mortality in hospitalized patients receiving favipiravir, and to contribute to the literature on this subject. Material and method: PCR-positive patients who were hospitalized in our hospital with the diagnosis of COVID-19 between June 1 and July 1, 2020 were included in the study. The data of the patients were analyzed retrospectively. The patients were divided into 3 groups: those who started treatment with favipiravir, those who added favipiravir to the treatment regimen because there was no response to the first-line treatment, and those who did not receive favipiravir. Results: A total of 662 patients, mean age of 58.38±18.86 years and 59.4% male were included in the study. Mortality developed in 74 people, and the mortality rate was 11.17%. More than 50% involvement was detected in thorax CT in 69% of hospitalized COVID-19 PCR positive patients. The mean age of those who added favipiravir to the treatment was 66.95±15.88 years, which was statistically significantly higher than the group that was not added. Those who received favipiravir from baseline had higher viral clearance rates. In our study, it was found that 17.9% of those who received it from the beginning and 34.0% of those who were added later developed mortality on the 28th day, and there was a statistically significant difference between these groups. Conclusion: Those who received favipiravir from baseline had higher viral clearance rates and lower mortality. It can be concluded that late initiation of favipiravir treatment increases mortality.