The purpose of this article is to describe how the concepts of continuum damage mechanics can be applied to modeling of polyethylene materials under different loading conditions. The increasing use of polyethylene in diverse applications motivates the need for understanding how its molecular properties relate to the overall behavior of the material. Although microstructure and mechanical properties of polymers have been the subject of several studies, the irreversible microstructural rearrangements occurring at large deformations are not completely understood. In this work, a three-dimensional damage constitutive model for polyethylene is proposed. The material is analyzed from a microscopic viewpoint and considered as an aggregate of crystals. The model regards the crystals as rigid-viscoplastic and incorporates the effects of atomic debonding on the overall mechanical behavior. To illustrate the capability of the proposed model, two simulations are carried out to capture the macroscopic stress-strain behavior and texture evolution under uniaxial tension and simple shear loading conditions. The results are compared with experimental data and numerical simulations from other references.