The McEliece and the Niederreiter public key cryptosystems (PKC) are supposed to be secure in a post quantum world [4] because there is no eﰃcient quantum algorithm for the underlying problems upon which these cryptosystems are built. The purpose of this article is to describe in what the structure of the McEliece PKC is sensitive to fault injection. We present the injection fault in the McEliece scheme using binary Goppa codes and in two variants using quasi-cyclic alternant and quasi- dyadic binary Goppa codes, and describe the main diﰀerence of those constructions in this context. Keywords: post-quantum cryptography, code-based cryptography, side-channel attacks.