This report presents site-dependent design response spectra which account for the effects of the soils and earthquakes that occur in Washington State. A base spectrum and soil amplification spectra are developed that are correlated with a mapped severity coefficient. The base spectrum is selected with consideration given to the special characteristics of the subduction zone earthquakes likely to occur in this area. The computer program SHAKE is used to develop the soil amplification spectra. Soil profiles from 123 boring logs from actual bridge sites in Washington are used in this research. The results are intended to replace corresponding sections of currently used AASHTO guidelines.