In L 2 (R 3 ), we consider the unperturbed Stark operator H 0 (i.e., the Schrödinger operator with a linear potential) and its perturbation H = H 0 + V by an infinitely smooth compactly supported potential V . The large energy asymptotic expansion for the modified perturbation determinant for the pair (H 0 , H) is obtained and explicit formulae for the coefficients in this expansion are given. By a standard procedure, this expansion yields trace formulae of the Buslaev-Faddeev type.