It is estimated that at least 29.1 million Americans, or 9.3% of the US population, currently have diabetes (1 ), a disease characterized by impaired insulin action and/or production. Although type 2 diabetes (T2D), 4 which accounts for ÏŸ90% of diagnosed diabetes, is largely predictable through anthropometric, lifestyle, and clinical factors, and is preventable through diet and lifestyle modifications, the metabolic pathways underlying its development and progression are incompletely understood. The rapidly developing area of metabolomics, which is designed to quantitatively profile a large number of small molecules in cells or biofluids, has emerged as a promising approach to elucidate altered metabolic pathways and discover novel biomarkers in T2D.The past several years have seen the initial success of metabolomics in identifying novel biomarkers for insulin resistance and T2D. The above studies have revealed several promising novel biomarkers of T2D; however, they have been limited in the number of metabolites detected and analyzed (approximately 100 -200 targeted metabolites). In an article in the current issue of Clinical Chemistry, Drogan et al. (7 ) applied an untargeted metabolomic approach with a coverage of ÏŸ4500 metabolite features by ultraperformance LC-MS with a protocol specifically designed for large-scale metabolomic studies regarding robustness and repeatability. The study was nested in the wellcharacterized European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort, which has collected blood samples, detailed measurements of anthropometric parameters and blood pressure, dietary and lifestyle questionnaires, and verified clinical outcomes during a follow-up period of approximately 20 years. The study included 300 incident T2D cases and 300 randomly selected controls matched on age, sex, fasting time, time of day of blood sampling, and season at blood sampling. The study population was then randomly split into 2 internal substudies, each containing 150 matched case-control pairs to verify the internal consistency of findings. The authors observed that diverse altered classes of metabolites, including 6 lipids and 7 nonlipids, preceded the onset of overt T2D by a median of 6 years. More specifically, higher serum concentrations of lipids in the phosphatidylcholine (PC) class, PC(22:4/ dm18:0) and PC(O-18:0/22:5), and lower concentrations of PC(O-20:0/O-20:0) were related to a higher risk of T2D. Higher serum concentrations of purine nucleotide isopentenyladenosine-5Đ-monophosphate showed an association with a higher risk of T2D, and for the large group of hexose sugars and derivatives, both positive and negative associations were detected. These findings were internally consistent and significant in the split samples. Several of the metabolites, including PC(O-20:0/ O-20:0), were linked to T2D incidence for the first time. Although further validation in independent external cohorts is warranted, these findings underscore the po-