Novel coronavirus disease (COVID-19) is a highly contagious disease caused by severe acute respiratory distress syndrome coronavirus-2 that has resulted in the current global pandemic. Currently, there is no available treatment proven to be effective against COVID-19, but multiple medications, including hydroxychloroquine (HCQ), are used off label. We report the case of a 60-year-old woman without any cardiac history who developed right bundle brunch block and critically prolonged corrected electrocardiographic QT interval (QTc 631 ms) after treatment for 3 days with HCQ, which resolved on discontinuation of the medication. This case highlights a significant and potentially life-threatening complication of HCQ use.