First, a screening of catalysts was performed, using four ruthenium complexes known for their ability to form hydride species and/or perform decarboxylation reactions. The decarboxylation of methyl formate was first tested with 3 mol% of [(MACHO)RuH(CO)Cl] 1, efficient in the transfer hydrogenation of esters. After 3 days at 160 °C in the presence of 20 mol% of LiI, we observed 23 % conversion, but only methyl iodide and methanol were observed by 1 H NMR in 15 and 8 % yield respectively (Table , Entry 1). The acetate complex [(MACHO)Ru(OAc)2] 2 led to lower conversion and only side-products were detected. (Table , Entry 2,). The combination of rac-P4 and [(p-cymene)Ru(OAc)2] 3 was also tested, as it was described by Gonsalvi et al. to be efficient in the decarboxylation of formic acid to H2 and CO2. The conversion is significant (95 %) after 3 days, and only traces of methyl iodide and 7 % methanol are observed (Table , Entry 3). Finally, [(triphos)Ru(OAc)2] 4, also used in the disproportionation of formic acid, was found to be the most efficient catalyst and full conversion was observed after 24 h, resulting in the selective formation of methane in 95 % yield: only traces of methanol and methyl iodide were observed (Table , Entry 4). Lowering the temperature to 100°C was however detrimental to the catalytic activity, which drastically decreased, and only 8% of methyl formate was converted into methanol and methyl iodide: no methane was observed in 1 H NMR (Table , Entry 5). Blank experiments (Table , Entries 5 and 6) confirmed that both LiI and the ruthenium complex are required to obtain methane. Furthermore, LiI alone is able to form iodomethane, which supports our mechanistic hypothesis where iodomethane is a key intermediate of the reaction. The influence of the solvent was then tested: replacing THF with an apolar solvent, benzene-d6, led to a very low (12 %) conversion and mostly methyl iodide was observed (Table , Entry 8,). In acetonitrile, the reaction did not form methane or methyl iodide, and only methanol as well as unidentified peaks were detected (Table , Entry 9), which may arise from the decomposition of acetonitrile. In DMF-d7, methane was formed in 73 %yield, albeit together with 24 % of methanol after three days of reaction (Table , Entry 10).