Summary: On the basis of the one-dimensional Schapery representation for nonlinear viscoelasticity, a three-dimensional constitutive model incorporating the effects of temperature and physical aging is developed for isotropic nonlinear viscoelastic materials. Adopting the assumption that the hydrostatic and deviatoric responses are uncoupled, the constitutive equation is expressed in incremental form for both compressible and incompressible materials, with the hereditary integral updated at the end of each time increment by recursive computation. The proposed model is implemented in the finite element package MARC. Numerical examples are given to demonstrate the effectiveness of the model and the numerical algorithms.