The following research work covering the complicated subject of public space, this space is intended to be studied from the perspective of a border city as is the case: Ciudad Juarez Chihuahua and El Paso Texas. The intention is to be able to identify facts that modify the urban morphology and the configuration of the public spaces by analyzing their characteristics and uses but always keeping in perspective the fact to be a frontier, as in this case: Mexico-USA. The methodology used on this research is mixed-qualitative and quantitative comparative nature, supported of theories of urban public space, sociological concepts and statistical data from both cities to obtain results which reveal the differences of urban models in both urban models Mexicans and Americans, but especially the cities called " mirror cities ", as is the case of study but identifying how it affects the perspective of traditional public spaces such as the down town of both cities.