Diffuse large B-cell lymphoma is an aggressive, genetically heterogenerous disease and the most common type of non-Hodgkin lymphoma among adults. To gain further insights into the etiology of DLBCL and to discover potential diseaserelated factors, we performed a serum lipid analysis on a subset of individuals from a population-based NHL case-control study. An untargeted mass-spectrometry-based metabolomics platform was used to analyze serum samples from 100 DLBCL patients and 100 healthy matched controls. Significantly elevated levels of the endocannabinoid, 2-arachidonoylglycerol (2-AG), were detected in the serum of DLBCL patients (121%, P<0.05). In the male controls, elevated 2-AG levels were observed in those who were overweight (BMI ≥25 – <30 kg/m2; 108%, P<0.01) and obese (BMI ≥30 kg/m2; 118%, P<0.001) compared to those with a BMI <25 kg/m2. DLBCL cell lines treated with exogenous 2-AG across a range of concentrations, exhibited heterogenous responses: proliferation rates were markedly higher in 4 cell lines by 22%-68% (P<0.001) and lower in 8 by 20%-75% (P<0.001). The combined findings of elevated 2-AG levels in DLBCL patients and the proliferative effects of 2-AG on a subset of DLBCL cell lines suggests that 2-AG may play a potential role in the pathogenesis or progression of a subset of DLBCLs.