[1] We present carbon isotopic signatures of methanol and acetaldehyde emitted from biomass burning sources using laboratory experiments. The respective d 13 C of methanol and acetaldehyde emitted from burning experiments of five plant materials (three C 3 and two C 4 plants) were À20-À46% and À11 -À25%. The variation in d 13 C of methanol depends on the d 13 C of the fuel biomass and burning conditions, but the variation in d 13 C of acetaldehyde depends on the d 13 C of fuel biomass and is independent of burning conditions. Combining these observations with previously reported global distributions of fire types, burning conditions, amounts of biomass burned, vegetation types, and emission factors, we estimated the global isotopic signature for biomass burning source as À33 ± 16% for methanol. Citation: Yamada, K., R. Hattori, Y. Ito, H. Shibata, and N. Yoshida (2009), Carbon isotopic signatures of methanol and acetaldehyde emitted from biomass burning source,