El Paso, Texas, and Ciudad Juárez, Chihuahua, share a common border divided by the channeled and weakly flowing Rio Grande. The twin cities, with a combined population of over a million, are located in a valley between two mountain ranges. They share a common air shed, mutual sources of water supply, and the ever-present threat of disease which, of course, does not recognize the artificial national boundary dividing the two cities.

How have the sister cities and their respective governments at the local, state, and federal levels attempted to solve their common health and environmental problems? This paper will briefly review the efforts to resolve and to solve common health and environmental problems between the two cities. What is necessary at the outset is some type of analytical framework to better understand the relations between the two cities.