Abstract. Let K be an algebraic number field and let (Gn) be a linear recurring sequence defined by Gn = λ 1 α n 1 +P 2 (n)α n 2 +· · ·+Pt(n)α n t , where λ 1 , α 1 , . . . , αt are non-zero elements of K and whereIn this paper we want to study the polynomial-exponential Diophantine equation f (Gn, x) = 0. We want to use a quantitative version of W. M. Schmidt's Subspace Theorem (due to J.-H. Evertse [8]) to calculate an upper bound for the number of solutions (n, x) under some additional assumptions.