There is a strong cross-border demographic and socioeconomic dynamic between Tijuana and San Diego; job opportunities in San Diego have brought it a growing population of Mexican origin. These two cities' interrelated economies bring about changes in the population and economic activity. This article examines the economic context from 1970 to 2010, including key events such as the Border industrialization Program, the Simpson-Rodino Act, the North American Free Trade Agreement, and the 2008 financial crisis. Tijuana's main employer is manufacturing, while in San Diego services and commerce are the main employers for workers of Mexican origin, who are increasing their participation in the professional services sector.