This study investigates unsteady aerodynamic responses of base-isolated high-rise buildings. First, an approximation method for motion-induced wind forces for time-domain analysis of high-buildings is suggested. Second, wind response analyses for base-isolated high-rise buildings composed of rubber isolators and lead dampers are carried out using approximated motion-induced wind forces. The following results were obtained. 1) Approximated values of motion-induced wind forces by the suggested method agree with forced vibration wind tunnel test values, and wind responses calculated by using these approximated motion-induced wind forces agree with aerodynamic model tests. 2) Unstable aerodynamic response could occur for base-isolated high-rise buildings with light structural density and low yield load of the lead dampers.