HIV prevalence in Maharashtra is one of the highest among Indian states. The specific objectives of this study were: to understand the patterns and drivers of migration/mobility of men who migrate for the purpose of work in the state of Maharashtra; to describe the characteristics of vulnerable subpopulations among migrant men; and to examine the determinants of high-risk sexual behavior among the subpopulations of migrant men with particular emphasis on the role of mobility in determining the sexual risk behavior. The present study clearly demonstrates that these male migrants, married or otherwise, retain strong connectivity to their native villages, but also show high levels of sexual activity—including significant levels of high-risk sexual activity—making it imperative to study the situation in the sending districts regarding HIV prevalence and spread. The indication from this study is clear: in the context of high-risk sexual behavior (among both married and unmarried migrants) and the low levels of knowledge, condom use, and risk perception, the chances of sending households and districts becoming areas of high HIV prevalence are great. Further exploration of the sexual behavior pattern in sending areas is necessary to obtain additional insights into the possible routes of HIV transmission