This document contains Guidelines for the seismic design of highway bridges. The Guidelines are the recommendations of a team of nationally recognized experts which included consulting engineers, academicians, State highway, and Federal agency representatives from throughout the United States. The Guidelines are comprehensive in nature and they embody several new concepts which are significant departures from existing design provisions. An extensive commentary documenting the basis for the Guidelines and an example demonstrating their use are included. A draft of the Guidelines was used to seismically redesign twenty-one bridges. Significant changes resulted from the redesigns and are reflected in this report. A summary of the redesigns is included.