The present invention pertains to a process for preventing the freezing of water in a structural component of a fuel cell system, especially in a component containing at least one movable part in the anode cycle of a fuel cell system as well as a fuel cell system with several fuel cells combined to form a fuel cell stack which has an anode side, a cathode side and a membrane arranged between the anode side and the cathode side, the anode sides of the fuel cells being joined together to form an anode cycle and which also includes a device for supplying fresh gaseous fuel, a drain valve which is designed for continuous or discontinuous bleeding off of at least part of the gases flowing in the anode cycle and at least one component having a moving part such as a fuel recirculation pump, the fuel recirculation pump feeding the exhaust gases emerging from the anode sides of the fuel cell and containing useful fuel back to the anode sides of the fuel cells.