OBJECTIVE:To analyze the fatigue severity of patients with idiopathic chronic fatigue(ICF) and to compare the severity of this group with that of healthy subjects.METHODS:one hundred and nine ICF patients and 98 healthy subjects were enrolled in this study.Fatigue severity was measured using the Korean-translated Chalder fatigue severity questionnaire.All subjects scored each item on a 10-point scale as a self-rating numeric scale(NRS),and additionally rated their feeling of general fatigue by visual analogue scale(VAS).RESULTS:The total NRS scores of patients with ICF was 53 ± 15 compared with 25 ± 14 of healthy subjects(2.4 folds for physical symptoms vs.1.7 folds for mental symptoms respectively).The VAS scores of patients with ICF were 2.7 times as high as those of healthy subjects.CONCLUSION:This report is the first to compare the severity of fatigue between ICF patients and healthy subjects.This study contains reference data applicable for the management of this disorder in field of complementary and alternative medicine.