Objective: The Coronavirus disease-2019 (COVID-19) pandemic has caused the death of many people worldwide. Treatment protocol had to be developed as soon as possible so drug combinations, whose reliability has not been fully disclosed, have started to be used. In this study, we aimed to evaluate the effect of azithromycin (AZT), hydroxychloroquine (HCQ), and favipiravir (FVR) combination on the corrected QT (QTc) interval. Material and Methods: Eighty-four consecutive COVID 19 patients were enrolled in the study. All patients received AZT and HCQ, however, FVR was added to the combination in 32 patients with severe pneumonia at the beginning. ECG characteristics of all patients before treatment and on the fifth day of treatment were compared. Results: There was no significant difference between the HCQ+AZT group (n=52) and HCQ+AZT+FVR groups (n=32) in terms of baseline clinical characteristics. QTc interval significantly prolonged on the fifth day of treatment in the HCQ+AZT group (413,75±30,13; 440,27±36,11 p<0.001) and in the HCQ+AZT+FVR group (426,65±32,83; 468,22±42,13 p<0.001). When both groups were compared in terms of ΔQTc, a significant increase was observed in the HCQ+AZT+FVR group compared to the HCQ+AZT group (40(-14/175), 23(-28/213) respectively, p=0.042). In seven of the patients, QTc> 500 ms was detected after the treatment, four patients in the HCQ+AZT+FVR group and three patients in the HCQ+AZT group. Conclusion: We observed that FVR caused more prolongation in the QTc interval when used with the combination of HCQ+AZT. We recommend that patients who receive this treatment be monitored more closely for QTc.