Acetylene (C2H2) is an important hydrocarbon species which is present in trace quantities in the troposphere and lower stratosphere. Potential loss processes for atmospheric C2H2 include reactions with OH, Cl, O, and Br as well as photodissociation. Rate data for the first three reactions are available in the literature, but the latter reaction has not been the subject of any previous studies. We have measured the rate constant for the reaction Br+C2H→MC2H2Br at four temperatures over the range 210--393 K and at pressures between 15 and 100 torr Ar. The technique employed as flash photolysis combined with time-resolved detection of atomic bromine via Br resonance radiation. The reaction was shown to be independent of total pressure (Ar) and temperature over the indicated ranges. The average of all experiments gives the value k=(4.0¿0.8)¿10-15 cm3 s-1, where the error is 2 standard deviations. The result is compared with previous data from our laboratory for reactions of H, Cl, OH, and NH2 with C2H2. Loss rates for atmospheric C2H2 have been calculated as a function of altitude for reactions with OH, Cl, O, and Br.