Fatigue is a common, under recognized, and poorly understood nonmotor symptom in Parkinson's disease (PD). Fatigue frequently presents early in PD, and its prevalence increases with disease progression, affecting up to 60% of patients. Fatigue has a negative impact on quality of life. Fatigue is often associated with other nonmotor symptoms, including sleep disturbance, excessive daytime sleepiness, and depression. Only a few reports have been published on the treatment of fatigue in PD (methylphenidate, levodopa, and pramipexole). Further well-designed studies, including physiotherapy, are necessary to develop more effective treatments for PD-associated fatigue. A number of patients with PD lose weight because of loss of fat. However, the evolution and determinants of weight loss are not well established. Possible determinants of weight loss in PD include loss of appetite, impaired hand-mouth coordination, difficulty in chewing and dysphagia, nausea, intestinal hypomotility, and increased energy requirements because of muscular rigidity and involuntary movements. Noticeable weight gain has repeatedly been reported after subthalamic or pallidal deep brain stimulation. Because low body weight is associated with negative health effects and a poor prognosis, monitoring weight and nutritional status should be part of PD management.