Background and Aim: The COVID-19 virus has influenced the whole world since late 2019 and has affected millions of people The combination of hydroxychloroquine (HQ) and azithromycin (AZ) has entered the protocols worldwide to reduce virus replication and take advantage of its immunomodulatory effects The frequency of QTc prolongation in combinational drug use, and its effect on the primary endpoint, as well as the predictive values of QTc prolongation are not clear Methods: The study was designed as a single-center, retrospective study 135 patients who received hydroxychloroquine, azithromycin and oseltamivir for suspected/definitive COVID-19 with viral pneumonia were examined Results: The mean age was 55 6±19 1 years and 61 (45%) patients were female According to the initial ECG values, the QTc1 value was found to be 422 44±35 72 ms, while the QTc2 value was 446 91±35 72 ms (p500 ms was 9 (6 6%) The number of patients with prolongation in QTc values >60 ms was 11 (8 1%) The sum of frequency of prolongation in QTc was 16 2% in intensive care unit patients, when the frequency was 1 5% in low-risk patients in the inpatient unit An elevation in troponin values >14 ng/L and a low GFR are predictors for QTc prolongation None of these patients developed a malignant arrhythmia or sudden cardiac death Conclusions: Hydroxychloroquine and azithromycin combinations used in COVID-19 patients cause a prolongation in the QTc The incidence of prolongation in QTc varies according to the comorbid characteristics and clinical status of the patients Before starting hydroxychloroquine and azithromycin, the risk factors and clinical status of the patients should be well evaluated