Metabolomics is the comprehensive study of the repertoire of small molecules present in cells and tissues. The identities, concentrations, and fluxes of these molecules are a final product of interactions between gene expression, protein expression, and the cellular environment. Recent advances in technology have enabled the measurement of large numbers of small molecules in blood samples. The technologies, which are being utilized, are high performance liquid chromatography with electrochemical detection and mass spectroscopy. Using these technologies we have been able to identify unique patterns of small molecules in patients with Parkinson's disease (PD) in our initial studies. We now intend to carry out further studies to determine how reliable these small molecule markers will be in identifying and diagnosing patients with PD and whether they may serve as a marker of disease progression.