The vibrational relaxation of HBr(v″= 1) has been studied by flash photolysis with kinetic absorption spectroscopy in the vacuum ultra-violet. Two photochemical systems have yielded this vibrationally excited species. On photolysing hydrogen bromide, HBr(v″= 1) arises from the energy transfer process, Br(42P½)+HBr(v″= 0)→Br(42P)+HBr(v″= 1). In the presence of added molecular bromine, the fast metathetical reaction H(12S½)+Br2→HBr(v″=n)+Br(42P½,) takes place and is followed by rapid vibrational exchange to yield a non-Boltzmann population in the first vibrational level. This latter process was a convenient source for energy transfer studies of HBr(v″= 1) and the probabilities for relaxation on collision with the species He, Ar, H2, HBr, HCl, N2, CO, CH4, SF6, Br2 and Br(42P) are reported for 300 K. These data are discussed within the context of existing theories for vibrational relaxation.