In this paper we establish some parabolicity criteria for maximal surfaces immersed into a Lorentzian product space of the form M 2 × R 1 , where M 2 is a connected Riemannian surface with non-negative Gaussian curvature and M 2 × R 1 is endowed with the Lorentzian product metric , = , M − dt 2 . In particular, and as an application of our main result, we deduce that every maximal graph over a starlike domain ⊆ M is parabolic. This allows us to give an alternative proof of the non-parametric version of the Calabi-Bernstein result for entire maximal graphs in M 2 × R 1 .