This article deals with the approximation properties of a generalization of an integral type operator in the sense of Favard-Szász type operators including Sheffer polynomials with graphics plotted using Maple.We investigate the order of convergence, in terms of the first and the second order modulus of continuity, Peetre’s K-functional and give theorems on convergence in weighted spaces of functions by means of weighted Korovkin type theorem. At the end of the work, we give some numerical examples