The US Food and Drug Administration (FDA) evaluated two commercial e-cigarettes and a nicotine replacement therapy inhaler in 2009 (DPATR-FY-09-23). Ethylene glycol (EG) and diethylene glycol (DEG) were included in this evaluation as potential impurities in e-cigarette formulations. DEG was found in one e-cigarette cartridge in the study (quantities were not included). The U.S. Pharmacopeia (USP) discusses permissible levels of EG and DEG in polyethylene glycol and glycerin (< 0.1%), the major components of most e-vapor product formulations. The USP only provides non-selective methods for the analysis of these potential contaminants in USP grade propylene glycol and glycerin. These methods are subject to potential interferences caused by flavor systems found in e-cigarette formulations. Therefore, the purpose of this work was to develop and validate a sensitive and selective method specifically for the quantitative screening of e-vapor formulations for EG and DEG. The method developed uses gas chromatography with mass spectrometry (GC/MS). All requirements for method validation were met such as linearity, accuracy, precision, limits of detection (LOD), and limits of quantitation (LOQ). The linearity was demonstrated with a coefficient of determination of >0.995 for the calibration range of 10 to 800 ug/g of e-cigarette formulation.