Biomarkers are very important indicators of normal and abnormal biological processes. Specific changes in pathologies, biochemistries and genetics can give us comprehensive information regarding the nature of any particular disease. A good biomarker should be precise and reliable, distinguishable between normal and interested disease, and differential between different diseases. It is believed that biomarkers have great potential in predicting chances for diseases, aiding in early diagnosis, and setting standards for the development of new remedies to treat diseases. New technologies have enabled scientists to identify biomarkers of several different neurodegenerative diseases. The followings, for instance, are only a few of the many new biomarkers that have been recently identified: the phosphorylated tau protein and aggregated Beta-amyloid peptide for Alzheimer's disease (AD), Alpha-synuclein contained Lewy bodies and altered dopamine transporter (DAT) imaging for Parkinson's disease (PD), SOD mutations for familial amyotrophic lateral sclerosis (ALS), and CAG repeats resulted from Huntington's gene mutations in Huntington's disease (HD). This article will focus on the most-recent findings of biomarkers belonging to the four mentioned neurodegenerative diseases.