Provided are an endoscope system and a method of operating the same that can avoid occurrence of electro-magnetic interference without influencing an image of an observation target.An endoscope system (10) includes at least any one of a processor device (16) that is attachable to and detachable from an endoscope (12) or a light source device (14) that is attachable to and detachable from the endoscope (12). In a case where the endoscope (12) is mounted on the processor device (16) or the light source device (14), the processor device (16) or the light source device (14) performs a request sequence in which a request signal, for requesting a start of execution of encoding processing with respect to digital image signals, is transmitted to the endoscope (12).