Parkinson’s disease is traditionally regarded as a movement disorder caused by the loss of dopaminergic neurons in the nigrostriatal system. However, we are becoming more and more aware that pathology of this disease is much wider than initially thought and that degeneration may involve many areas in both central and peripheral nervous systems. This is reflected in a wide spectrum of non-motor symptoms that involve sleep, psychiatric, cognitive, autonomic and sensory disorders. Non-motor symptoms occur in more than 98% of the patients with Parkinson’s disease. They can appear at anytime in the course of disease and are often present in the preclinical phase (pre-motor symptoms). The pre-motor symptoms can predate the onset of Parkinson’s disease and they could be used as biomarkers for identifying persons at risk for development of Parkinson’s disease. Early detection of Parkinson’s disease will be of considerable value when neuroprotective therapy becomes available. The non-motor symptoms become more frequent and more severe as the disease progresses. They often represent a huge burden for the patient and can cause a severe decrease in the quality of life. It is therefore very important to recognize and treat these symptoms, as this can significantly improve the patient’s well-being.