The present study proposes a new hydrostatic stress-dependent yield criterion and discusses coupled evolution of inelasticity and damage in polymer matrix materials. In addition, the study presents a constitutive model that simultaneously incorporates the evolution of inelasticity and damage. An associative flow rule is used for the evolution of inelastic strains. The damage growth model is coupled with the evolution of accumulated inelastic strain. Model predictions are compared with the experimental data in the literature. Further, attention is given to the growth and saturation of inelastic strain and damage before rupture. It is noted that the damage saturates at different values under tension, compression, and shear. Also, the damage saturation happens at lower strains, and then the inelastic strain evolution continues until rupture.