Synthetic binders are special paving materials manufactured by mixing polymers, resins, and oils. These materials may have improved mechanical properties as compared with the traditional modified bitumen. This work is part of a comprehensive study on the design of synthetic binders with selected mechanical properties. In this sense, upgraded mechanical properties of the final synthetic binder can be attained by understanding and correlating the mechanical properties of its individual constituents as a function of composition and temperature. With this aim, this work deals with the thermomechanical properties of recycled polymer/resin blends, over a wide range of temperature and composition. Recycled polymer/resin blends are thermorheologically complex materials, due to the development of multiphase domains depending on polymer concentration. Thus, these blends show a predominantly gel-like behavior at high polymer concentrations and a predominantly viscous behavior, with high thermal susceptibility, for low polymer concentrations. The dynamic viscosities of the blends, as a function of polymer concentration and temperature, can be predicted using a logarithmic mixing rule. POLYM. ENG. SCI., 2012. (C) 2011 Society of Plastics Engineers