This research presents the application of the TRANUS integrated land use and travel demand modeling software to estimate transborder origindestination (O-D) pairs by developing a travel demand model (TDM) that integrates the two border communities in a binational conurbation into a single transportation and economic system. Commercial and personal ties generate a tremendous amount of transborder traffic within binational conurbations along the U.S.Mexican border. With so much interaction, individual transportation networks from each country become a single transportation system connected through the ports of entry. Conventionally, each side of the border is modeled separately or through the use of external zonesthe area is not treated as a single, interconnected system. This research presents a methodology to estimate transborder O-D pairs and traffic flows with TRANUS. The case study of a binational TDM covering the El Paso, TexasCiudad Juarez, Mexico conurbation is presented. Results demonstrate encouraging findings from using TRANUS to estimate transborder O-D pairs for private trips. Furthermore, the methodology developed can be replicated in any conurbation along the U.S.Mexican border with a relatively limited data collection effort. Although traditional TDMs require extensive and expensive household surveys, which are difficult to conduct in binational settings, this research shows that it is possible to generate a reasonably reliable set of binational O-D matrices at a significantly lower cost and time investment by using TRANUS.