Catalytic reductive methylation of acetylhydrazine (AH) to dimethyl acetylhydrazine (DMAH) is a key step in the production of unsymmetrical dimethyl hydrazine (UDMH). The results of the present study show that the limiting step in this process is the hydrogenation of AH to mono methyl acetylhydrazine (MMAH). The kinetics of the hydrogenation of acetylhydrazone (AOH) using an activated carbon catalyst impregnated with 5 % palladium were studied in a stirred slurry reactor at 40-65 degrees C and 5-25 bar hydrogen pressure. Analysis of the data from this investigation indicates that the rate of hydrogenation is consistent with an Eley-Rideal reaction mechanism. The activation energy for the hydrogenation was determined as 44 kJ/mol.