This dissertation investigates how Regional Mexican radio in the U.S. tracks and drives changes in Mexican-American identity by combining different musical genres to create composite portraits of its audiences. Regional Mexican radio, which plays a mixture of ranchera, norteño, banda, and other regional Mexican genres to target a largely working-class audience of recent immigrants, is currently the most popular Spanish-language format in the U.S. Programmers for these stations act as mediators, navigating the public relation between notions of Latino identity constructed by national Spanish-language media conglomerates and local demographics. By modifying the generic composition of their playlists to strike a compromise between the two, they both monitor and produce the sociomusical categories that distinguish their listenership. Ethnographic research at Regional Mexican radio stations in Austin and San Antonio demonstrate the role that institutional organization plays in creating programming. National conglomerates that increasingly own these stations determine the broad outline of the industry, but local programmers make most decisions about programming content. Based on a historical review of Tejano radio, I argue that the musical mixtures created by Spanish-language programmers have responded to both past and present social and economic challenges facing Mexican-American immigrants. Through detailed analysis programming at five Regional Mexican stations, I argue that each variety of music played signifies regional, generational and gendered variations of Mexican-American identity that stations combine in different proportions to reflect local listenership. I also explore the role of station-sponsored events in gathering information about listeners. Events encourage listeners to embody their status as part of the Regional Mexican audience, a concept ultimately constructed by the radio stations. Ultimately, this dissertation adds to existing literatures on Spanish-language media, radio and Mexican-American music. / text