In this study, dynamic backcalculation was conducted on two selected Long-Term Pavement Performance (LTPP) sections, one from a cold climate zone and the other from a warmer climate zone. It was demonstrated that not only the viscoelastic dynamic modulus (| E*|) of the asphalt has been backcalculated from an extensive set of field data but also the master curve has been constructed successfully with the backcalculated data. It was also found that the backcalculated master curves were significantly different from those constructed with the LTPP | E*| coefficients. Furthermore, the backcalculated dynamic modulus was obtained from the same pavement sections after 12 to 14 years of service and compared with the initial baseline modulus.