Background: Since the pandemic began in 2020, Remdesivir has been widely used for the treatment of coronavirus disease-2019 (COVID-19). Here, we describe a case of a patient with COVID-19 who developed transient complete atrioventricular (AV) block and bradycardia after initiating treatment with Remdesivir. Case summary: A 72-year-old male with a history of atrial fibrillation and lung cancer was hospitalized for COVID-19. Electrocardiogram (ECG) on admission demonstrated atrial fibrillation and right bundle branch block. He was started on a course of Dexamethasone and Remdesivir. Within 24 h of starting Remdesivir, he was noted to be in atrial fibrillation with ventricular rates between 30 and 40 b.p.m. On Day 5 of Remdesivir therapy, ECG demonstrated complete AV block. Having completed the Remdesivir regimen, during the next 48 h, he was closely monitored, and the AV block resolved spontaneously. As he remained asymptomatic and had an adequate chronotropic response with activity, pacemaker implantation was not recommended. Discussion: Despite the widespread use of Remdesivir, there is little known information about its cardiac toxicity. Daily ECGs and close cardiac surveillance of patients who develop severe bradycardia or AV block are essential. Discontinuation of the medication usually results in the resolution of these cardiac disturbances.