The experiments in [1] on the crack propagation in elastomeric membranes subjected to various pre-stretch conditions has shown that crack propagates at a velocity proportional to the amount of pre-stretch, and that the fracture process is directly affected by the material viscosity. In this presentation, a phase-field fracture model is formulated within the context of finite viscoelasticity, and it is implemented numerically by finite elements to reproduce the experiments in [1]. The generalized Maxwell rheological model is extended to finite strains, as in [2]. In addition, a viscous dissipative contribution is incorporated into the evolution equation of fracture. As a result, the elastic strain and fracture phase-field evolve in time with two distinct characteristic times. Two-dimensional simulations are performed to reproduce the propagation of fracture in elastomeric membranes. The numerical results highlight the influence of viscosity in the fracture process. Attention is focused particularly on the effects of the two characteristic times on the advancement of the crack and on the strain relaxation of the material surrounding the crack tip.