Gallium-containing forms of MFI zeolite have been subjected to adsorption of 1- and 2-propanamine, and the results of subsequent thermal treatment have been analyzed and compared to literature reports for propanamines adsorbed on proton forms of MFI. Zeolitic gallium cations show completely different behavior from zeolitic protons, including a propanamine decomposition mechanism which is different from Hofmann elimination. In this mechanism NH3 is desorbed at temperatures as much as 160 K below that of H-MFI. Major differences in the decomposition chemistry of the two amines were also observed when Ga cations were present.