INTRODUCTION: Chronic fatigue syndrome (CFS) is a condition of prolonged and disabling fatigue, which is accompanied by characteristic constitutional and neuropsychiatric symptoms. In children and adolescents, this condition occurring at a developmentally vulnerable time adds to the disability affecting self-concept, autonomy, body image, socialisation, sexuality and academic problems. This case series looks at the effects of a graded exercise programme on physical outcomes, fatigue and mental state in an adolescent population. METHODS: Data sets from 16 adolescents who completed combined exercise training as part of the 4-week inpatient intensive CFS programme at the Austin Hospital, Melbourne were analysed. All patients completed an exercise assessment and three questionnaires before beginning any training. A paediatrician (LL) confirmed the diagnosis according to the Fukuda criteria in all patients. Exercise was carefully supervised and prescribed daily by an exercise physiologist (BG) according to each individual's ability and response with the basic aim of increasing exercise tolerance and improving muscle strength and endurance. RESULTS: There was an 18% improvement in volitional time to fatigue (P= 0.02) and 17% improvement in peak oxygen uptake (VO(2peak)) (P= 0.01). Upper body strength and function improved with a remarkable 70% increase in the number of push-ups. Fatigue severity was reported to improve by 13% (P= 0.01) and depression index improved significantly by 42% (P= 0.02). CONCLUSIONS: The significance of these improvements cannot be underestimated as an improvement in physical capacity through increased time to fatigue and less severe fatigue allows adolescents to resume school, social and family activities.