This article examines comparative risk behaviors associated with methamphetamine use in a binational sample of women in the border cities of Tijuana, Mexico, and San Diego, CA. Specifically, the study examined the differences and similarities in drug use and sexual risk behavior and the patterns of initiation to methamphetamine use. The binational pilot sample consisted of 70 adult women in Tijuana and 55 women in San Diego. Although there were important differences in the presentation of risk behavior and patterns of initiation between the two binational samples, women on both sides of the US-Mexico border also showed remarkable similarities in their risk profile. Results from this study suggest that despite significant cultural and socioeconomic differences between the study cities, certain specific substance abuse patterns (e.g., methamphetamine use) in border regions with an increasing demographic exchange and integration are emerging as an "equalizer" of risk, capable of dissolving context-based differentiating factors, and creating a more homogenous subpopulation of substance users. Tables, figure, and references (Published Abstract)