Sur les donn{\'e}es endoscopiques dans le cas de l'endoscopie tordue

We give a simple combinatorial description of the elliptic endoscopic data of a twisted space under a group $G$, assuming that $G$ is semi-simple and simply connected. Assuming the same hypothesis and that the base field is a number field, we prove that, if two elliptic endoscopic data are equivalent almost everywhere, then they are equivalent.