Abstract: In order to provide a C-shaped clamp for clamping workpieces, comprising a C-shaped clamp bow, a spindle nut arranged at one end of the clamp bow, a clamping spindle mounted in the spindle nut and a support arranged at the other end of the clamp bow, which can be used in conjunction with auxiliary elements for clamping a workpiece, it is proposed that the clamp bow have a guide section with guide surfaces for guiding infinitely adjustable, auxiliary elements for the C-shaped clamp.