The electrosurgical unit is an electronical equipment that promots electrocoagulation and electrosurgery. As any other electronical equipment, its potential benefits can be annulated or its effects can be tragically disastrous to the patient, if there are omissions or misuse in its handling and maintenance. The analysis of the hazards involving burn injuries and interference problems with patients already monitorized contribute to the sa/ety of the patient in the operating room. Possible cause of burn injuries are analysed and the role of the nurse emphasized.