SUMMARYArrhythmias are a frequent occurrence in the daily practice of anesthesia and there are several factors implicated, including the drugs used for induction and maintenance of anesthesia. A case is presented of a 38-year old male patient, previously healthy, who developed a sick sinus syndrome manifested in the form of an accelerated nodal rhythm during general anesthesia, which reverted to sinus rhythm without requiring specific management. This condition is associated with multiple etiologies and its electrocardiographic manifestations may be diverse. It is important to recognize intra-operative arrhythmias, identify their possible causes, and treat them when necessary.