This study compared the associations between social support and HIV injection risk among Puerto Rican migrant (n = 221) and nonmigrant (n = 340) injection drug users in New York City. Practical and emotional support scales were developed from 8 items and examined by migrant status as predictors of risk. Bivariate and regression analysis were conducted with drug shooting gallery use, sharing needles, paraphernalia, and number of monthly injections as dependent variables. Migrants had lower emotional (2.82 vs. 3.19, p = 0.002) and practical (1.87 vs. 2.05; p = 0.051) support than nonmigrants. Controlling for age, sex and homelessness, emotional support was negatively associated to injection frequency and (standardized coefficient = -0.168, p = 0.020) gallery use (adjusted odds ration [AOR] = 0.76, confidence interval [CI] = 0.62-0.94, p = 0.011) among migrants and to an almost two fold increase in sharing syringes (AOR= 1.87, CI = 1.02-3.43; p = 0.041) among nonmigrants. The findings suggest that though migrants have less support than nonmigrants do, their support reduces risk and thus their likelihood of injection-related HIV infection.