The pyrolysis of glycerol was carried out over carbonaceous catalysts to produce synthesis gas (up to 81vol.%). The catalytic effect of two activated carbons was tested and compared with quartz glass chips as packing materials in a fixed-bed reactor. The main advantage of using a carbonaceous catalyst seems to be its higher selectivity toward hydrogen, resulting in a synthesis gas with a greater H 2 /CO ratio.The influence of the heating method (electrical furnace and microwave oven) and temperature (from 400 to 900°C) on the pyrolysis of glycerol over a selected activated carbon was also studied. As a result, an elevated gas fraction with a higher H 2 +CO composition was obtained under microwave heating, even at low temperatures. This proves that microwave heating could be used to upgrade the industrial surplus generated from bio-diesel production.