NOVELTY - The operating procedure for a fuel cell system with a reformer (3) for production of hydrogen from a hydrocarbon mixture by partial oxidation and with unit (5, 7, 8) that process the reformats (4) obtained in the reformer, in which after the starting of the system, the system components such as the reformers and/or the unit are heated at operating temperature, before the system is fully operationally operated. During the heating of the system components, a partial quantity of the reformat in a state after the withdrawal from the unit is recalculated in the reformer.    USE - For operating a fuel cell system for motor vehicle.    ADVANTAGE - The operating procedure for a fuel cell system accompanies a reduction of the partial pressure through increasing of the air ratio, which causes thermodynamically a reduction of the soot (carbon black) formation and depositing mechanisms.    DETAILED DESCRIPTION - The operating procedure for a fuel cell system with a reformer (3) for production of hydrogen from a hydrocarbon mixture by partial oxidation and with unit (5, 7, 8) that process the reformats (4) obtained in the reformer, in which after the starting of the system, the system components such as the reformers and/or the unit are heated at operating temperature, before the system is fully operationally operated. During the heating of the system components, a partial quantity of the reformat in a state after the withdrawal from the unit is recalculated in the reformer, so that the reformers during the heating in relation to the operation mode, shows its operating temperature, with which the system based on the recirculating with higher oxygen content can be operated. The reformats to be recirculated is cooled-off and/or conveyed by means of a conveyor device. The unit processing the reformats is an auxiliary power unit of a motor vehicle and/or a burner for heating-up a system component.    DESCRIPTION OF DRAWING(S) - The diagram shows a operating procedure for a fuel cell system:    Reformer; (3)    Reformats; (4)    Processing unit; (5, 7, 8)    Heat exchanger; (9)    Air flow. (11)