(E,Z)‐2‐bromo‐1‐(2,4‐dichlorophenyl)vinyl bis[ethyl‐2H5] phosphate ([2H10]bromfenvinphos), a regiospecifically deuterium‐labelled pesticide, was synthesized in two steps starting from [2H6]ethanol, phosphorus trichloride and 2,4‐dichlorophenacylidene bromide, and fully characterized. The deuterated biologically active bromfenvinphos is an important compound for the advancement of environmental degradation testing and some mass spectrometric studies. Copyright © 2011 John Wiley & Sons, Ltd.