Repair method for guide vanes (10, 10') of a gas turbine, in particular an aircraft gas turbine, comprising the following steps: providing at least one guide vane (10, 10') to be maintained; detecting the actual geometry of the guide vane (10, 10') to be maintained using at least one contactless measuring method; comparing the actual geometry of the guide vane (10, 10') detected by the contactless measurement method with a predetermined desired geometry for a corresponding guide vane type; calculating a target geometry for the guide vane (10, 10') to be maintained, which corresponds as far as possible to the desired geometry, such that, using optimization parameters, the desired geometry of the guide vane (10, 10') to be maintained is approximated at least in portions along its flow contour; applying material along a suction side (16, 16') of the flow contour of the guide vane (10, 10') from a leading edge (18, 18') to a trailing edge (20, 20') of the guide vane (10, 10') to be maintained and machine removal of applied material along a suction side (16, 16') of the flow contour of the guide vane (10, 10') from a leading edge (18, 18') to a trailing edge (20, 20') of the guide vane (10, 10') to be maintained, such that the calculated target geometry is produced, characterized in that the target geometry of the guide vane (10, 10') to be maintained is calculated and restored such that the flow contour in the region of the A4 cross-section of the guide vane (10, 10') to be maintained is approximated as effectively as possible to the flow contour of the desired geometry in the region of the A4 cross-section, the A4 cross-section being defined as the distance between two adjacent guide vanes (10, 10'), which extends between a central region of the suction side of the guide vane to be maintained to a region of the trailing edge of the adjacent guide vane, and in that the provided guide vane (10, 10') is removed from the first high-pressure turbine stage of a high-pressure turbine directly following the combustion chamber. providing at least one guide vane (10, 10') to be maintained; detecting the actual geometry of the guide vane (10, 10') to be maintained using at least one contactless measuring method; comparing the actual geometry of the guide vane (10, 10') detected by the contactless measurement method with a predetermined desired geometry for a corresponding guide vane type; calculating a target geometry for the guide vane (10, 10') to be maintained, which corresponds as far as possible to the desired geometry, such that, using optimization parameters, the desired geometry of the guide vane (10, 10') to be maintained is approximated at least in portions along its flow contour; applying material along a suction side (16, 16') of the flow contour of the guide vane (10, 10') from a leading edge (18, 18') to a trailing edge (20, 20') of the guide vane (10, 10') to be maintained and machine removal of applied material along a suction side (16, 16') of the flow contour of the guide vane (10, 10') from a leading edge (18, 18') to a trailing edge (20, 20') of the guide vane (10, 10') to be maintained, such that the calculated target geometry is produced, characterized in that the target geometry of the guide vane (10, 10') to be maintained is calculated and restored such that the flow contour in the region of the A4 cross-section of the guide vane (10, 10') to be maintained is approximated as effectively as possible to the flow contour of the desired geometry in the region of the A4 cross-section, the A4 cross-section being defined as the distance between two adjacent guide vanes (10, 10'), which extends between a central region of the suction side of the guide vane to be maintained to a region of the trailing edge of the adjacent guide vane, and in that the provided guide vane (10, 10') is removed from the first high-pressure turbine stage of a high-pressure turbine directly following the combustion chamber.