The invention relates to a method for starting an internal combustion engine (ICE) operating with combustible gas, with an internal combustion system, especially a large gas engine, according to which burnable gas/air mixture is formed in the admission system (I), especially in a gas mixer (9), upstream from a charger (7), and during the starting phase, compressed air is at least temporarily blown into the cylinder chambers of at least one group (B) of cylinders (1, 4, 5). In order to enable a reliable cold start of the internal combustion engine, the following steps are carried out: the pre-combustion chambers of at least the first group of cylinders are pre-heated to a defined pre-heating temperature; a self-igniting pilot fuel is introduced into the pre-combustion chambers of at least one group (A) of cylinders (2, 3, 6) when a defined rotational speed (n
1 ) is reached; the gas/air mixture is ignited in the cylinder chambers of said cylinders by means of the self-igniting pilot fuel; and the supply of pressurised air to the respective cylinders is stopped after the ignition of the gas/air mixture blown into the cylinder chambers.