Let G be a finite group and
$\mathrm {Irr}(G)$
the set of all irreducible complex characters of G. Define the codegree of
$\chi \in \mathrm {Irr}(G)$
as
$\mathrm {cod}(\chi ):={|G:\mathrm {ker}(\chi ) |}/{\chi (1)}$
and denote by
$\mathrm {cod}(G):=\{\mathrm {cod}(\chi ) \mid \chi \in \mathrm {Irr}(G)\}$
the codegree set of G. Let H be one of the
$26$
sporadic simple groups. We show that H is determined up to isomorphism by cod
$(H)$
.