Two cases of pre-excitation syndrome are reported and the anaesthesiological management adopted is discussed. After a brief overview of the pathophysiology of the syndrome relative indications and contraindications of the main anaesthetic drugs and volatile agents are analyzed. The high incidence of perioperative atrial fibrillation, atrial flutter or supraventricular tachycardia and the importance of maintaining sinus rhythm is recalled. The task confronting the anaesthetist is to ensure an adequate level of anaesthesia during induction and maintenance while carefully selecting specific drugs associated with minor cardiovascular side effects. In the Authors' experience benzodiazepines, fentanyl, vecuronium and isoflurane have proved to be the most adequate choice for this type of patient.