A large number of Mexican migrants are deported to Mexico and released in the North Mexican border region every year. Despite their volume and high vulnerability, little is known about the level of HIV infection and related risk behaviors among this hard-to-reach population. We conducted a cross-sectional, probability survey with deported Mexican migrants in Tijuana, Mexico (N = 693) and estimated levels of HIV infection and behavioral risk factors among this migrant flow. The sample and population estimated rates of HIV for deported males were 1.23 and 0.80 %, respectively. No positive cases were found among the female sample. We found high lifetime rates of reported sexually transmitted infections (22.3 %) and last 12-months rates of unprotected sex (63.0 %), sex with multiple sexual partners (18.1 %), casual partners (25.7 %), and sex workers (8.6 %), compared to U.S. and Mexico adults. HIV prevention, testing, and treatment programs for this large, vulnerable, and transnational population need to be implemented in both the U.S. and Mexico.