A positioning and clamping system, in particular for positioning and clamping a workpiece-bearing pallet 1 on a pallet receiving table 2, consists of at least two conical supports 4 arranged spaced from each other on the pallet receiving table 2 and at least two tapered sleeves 3 adapted to cooperate with the conical supports, the tapered sleeves being connected to the pallet 1 on the side which is to be located on the table. The at least one cone angle α1, α2 of one of the conical supports 4 and the tapered sleeve 3 adapted to cooperate therewith has an angle size which is suitable for the introduction of a self-locking connection between the support and the tapered sleeve upon cooperation thereof.