Abstract: An ignition system for rocket engine combustion chambers which are operated by non-hypergolic propellant components and particularly for the pre-combustion chambers of main stream engines of this type, comprises a main combustion chamber having injector means for injecting a propellant component into the combustion chamber for combustion therein. Since the propellant components employed are non-hypergolically reactive, they are ignited by an ignition agent which is produced by the pressure of a first propellant component which is non-hypergolically reactive with the ignition agent into the combustion chamber. The second propellant component which reacts with the ignition agent hypergolically is also introduced into the combustion chamber so that ignition takes place immediately.