A combination of microelasticity, phase-field description of grain structures, and first-principles calculations is proposed to predict the effective elastic properties of polycrystals. As an example, using the single crystal elastic constants from first-principles calculations and a polycrystalline microstructure from a phase-field simulation as inputs, the effective elastic moduli of polycrystalline magnesium are obtained as a function of temperature and compared with available experimental measurements. The texture effect on the effective elastic moduli is also examined. The proposed integrated model will make it possible to model not only the temporal evolution of microstructures but also the temporal evolution of properties using the phase-field method. © 2012 Elsevier B.V.