Abstract: Curved steel box-girder bridges are aesthetically pleasing and functionally effective, particularly at highway interchanges with curved alignments. A parametric analytical study of the seismic behavior of this type of bridges is performed. The study should be useful to the bridge industry, because of the need to construct these bridges in urban areas with tight right-of way restrictions, including earthquake-prone regions, and the fact that current specifications for horizontally curved highway bridges and other available information do not address sufficiently the seismic behavior of these bridges. A three-dimensional finite element model of an existing two-span continuous bridge with curved steel box-girders is analyzed for site-specific earthquake loads. Multiple parameters of the model are evaluated, including girder curvature, bearing condition, diaphragm spacing and free vibration characteristics. Results of the study with potential design recommendations are outlined. Seismic criteria by local and national specifications are contrasted and discussed in light of the analysis results.