Summary: ``In this paper we classify isogeny classes of global $\ssf G$-shtukas over a smooth projective curve $C/\Bbb F_q$ (or equivalently $\sigma$-conjugacy classes in $\ssf G(\ssf F\otimes_{\Bbb F_q}\overline{\Bbb F_q})$ where $\ssf F$ is the field of rational functions of $C$) by two invariants $\overline\kappa$, $\overline\nu$ extending previous works of Kottwitz. This result can be applied to study points of moduli spaces of $\ssf G$-shtukas and thus is helpful to calculate their cohomology.''