This article deals with the approximation properties of the bivariate operators which are the combination of Bernstein-Chlodowsky operators and the Szász operators involving Appell polynomials. We investigate the degree of approximation of the operators with the help of the complete modulus of continuity and the partial moduli of continuity. In the last section of the paper, we introduce the generalized Boolean sum (GBS) of these bivariate Chlodowsky-Szasz-Appell-type operators and examine the order of approximation in the Bögel space of continuous functions by means of the mixed modulus of smoothness. © 2017 by the Tusi Mathematical Research Group.