Syncope is a transient loss of consciousness with spontaneous return to the patient's baseline mental status. Although the exact etiology of syncope is frequently not ascertained, careful history and physical examination can determine the cause for the majority of those patients that can be diagnosed. Certain diagnoses, especially cardiac dysrhythmias, can be potentially life-threatening and require proper evaluation and observation. Safe disposition of the patient requires a careful evaluation in the prehospital setting and appropriate explanation to those who frequently have no symptoms at time of evaluation.