Mobility is not a new phenomenon, people move for many reasons and factors that drive mobility often stem from unequal distribution of resources, climate change, conflict and political unrest. In India, for the poor and for the people from less developed area, migrate to developed area for better economic opportunities, considering a migration as an opportunity to change their life. But migration is not an unmixed blessing, has some serious negative impacts as well. In recent year’s studies found that migrants are disadvantaged in many ways, which lead them to seek alternative support that may engage migrants in risky behaviors like visiting to sex workers, injecting drugs, drinking alcohols etc. making them more vulnerable to HIV infection. Delhi is the major destination for the migrants from less developed cities/states in India. So in this context, this paper intends to examine the relationship between migration and HIV prevalence among the migrants to Delhi. Also our aim is to examine the socio-economic conditions that increase the degree of vulnerability to HIV/AIDS. For the purpose we have a sample of 40 HIV patients who are migrants from Bihar and Uttar Pradesh in Delhi and 10 HIV patients who belong to Delhi. Using primary data collected through field survey and observation method, it is observed that the lower education status, poor wage and being separated from the life partners make migrants susceptible and vulnerable to sexually transmitted diseases especially HIV/ AIDS. It is found that after hard work the poor migrants resort to drinking wine and enjoy with sex workers, which is an important way of getting infected. Hence the migrant's previous conditions and present circumstances make them more prone to HIV infection. The Findings of the study are revealing that it’s become very necessary to implement effective programs that can aware migrants to prevent themselves from HIV infection and to lead a better life.