There is a paucity of studies acknowledging the existence of alternative food sources, and factors associated with food purchasing from three common alternative sources: vendedores (mobile food vendors), pulgas (flea markets), and vecinos/amigos (neighbors/friends). This analysis aims to examine the use of alternative food sources by Mexican-origin women from Texas-border colonias and determine factors associated with their use. The design was cross-sectional. Promotora-researchers (promotoras de salud trained in research methods) recruited 610 Mexican-origin women from 44 colonias and conducted in-person surveys. Surveys included participant characteristics and measures of food environment use and household food security. Statistical analyses included separate logistic regressions, modeled for food purchase from mobile food vendors, pulgas, or neighbors/friends. Child food insecurity was associated with purchasing food from mobile food vendors, while household food security was associated with using pulgas or neighbors/friends. School nutrition program participants were more likely to live in households that depend on alternative food sources. Efforts to increase healthful food consumption such as fruits and vegetables should acknowledge all potential food sources (traditional, convenience, nontraditional, and alternative), especially those preferred by colonia residents. Current findings support the conceptual broadening of the retail food environment, and the importance of linking use with spatial access (proximity) to more accurately depict access to food sources.