The reaction of H atoms with C3H6 was investigated in an isothermal flow system in the range 195-390 DegK and 1.6-20 Torr, resp. The distribution of stable products was studied by gas chromatog. and mass spectrometry, and was pressure- and temp. -dependent for all (H, C3H8, C2H4, C2H6, CH4, iso-C4H10) except H. By detg. the H atom concns. using ESR spectroscopy, the rate consts. for H atom addn. to terminal and non-terminal olefinic positions was evaluated. A mechanism accounting for the obsd. products was discussed. Relative and abs. rate consts. of some individual reactions were detd. from product distribution.