Migrants and recent immigrants in the US constitute a large population that is vulnerable to HIV. From March 2005 to February 2007, three community-based organizations conducted rapid HIV testing among migrants in five states. Participants were asked to complete a survey on sociodemographics, HIV-risk behaviors, and HIV-testing histories with the aim of understanding factors associated with HIV testing. Among 5,247 persons tested, 6 (0.1 %) were HIV-positive. Among 3,135 persons who completed surveys, more than half had never been tested for HIV previously (59 %). Participants reported high levels of HIV-risk behaviors in the past year, including 2 or more sex partners (45 %), sex while high/drunk (30 %), and transactional sex (29 %). Multivariate analysis identified several factors independently associated with decreased likelihood of prior HIV testing, including poor spoken English. Continued efforts are needed to ensure that migrant populations have improved access to HIV testing and prevention services. Understanding factors associated with migrants' lack of previous HIV testing may help focus these efforts.