  The present work deals with the mathematical investigation of some
generalizations of the Sz\'{a}sz operators. In this work, the multiple Sheffer
polynomials are introduced. The generalization of Sz\'{a}sz operators involving
multiple Sheffer polynomials are considered. Convergence properties of these
operators are verified with the help of the universal Korovkin-type property
and the order of approximation is calculated by using classical modulus of
continuity. The theoretical results are exemplified choosing the special cases
of multiple Sheffer polynomials.
