simple expression is proposed to estimate the fundamental period of vibration for concrete Shear Wall (SW) buildings. Most seismic codes specify empirical period formulas for seismic design. In this study, fundamental period data for concrete SW buildings recorded during California earthquakes between 1971 and 1994 were compared with the current US code formulas. It is shown that these formulas are inadequate for estimation of the fundamental period of concrete SW buildings. A closed-form period solution based on Rayleigh's method using SW displacement as a parameter is proposed to estimate the fundamental period of concrete SW buildings in low, moderate, and high seismicity regions. The accuracy of the closed-form solution is veried using recorded periods, and it conrms that the proposed expression provides reasonable estimates of the lower bound of a period. The results show that the fundamental period of concrete SW buildings depends signicantly on the displacement and mechanical properties of the SW.