A fuel injection system for an internal combustion engine is proposed. The fuel injection system has a high pressure part and a low pressure part. In the high pressure part, fuel is fed from at least one high pressure accumulator/reservoir to at least one fuel injector. In the low pressure part, the at least one fuel injector is connected to at least one low pressure accumulator/reservoir, wherein a pressure is maintained in the at least one low pressure accumulator by at least one pressure holding valve. Furthermore, the fuel injection system has at least one device for the after-treatment of exhaust gases of the internal combustion engine in an exhaust gas section. Furthermore, the fuel injection system has at least one metering device for the metered introduction of fuel into the exhaust gas section. Said at least one metering device is connected hydraulically to the at least one low pressure accumulator.