Throughout the world, many migrant and mobile populations are at elevated risk for HIV. Iran has a large immigrant population from neighboring Afghanistan; however, few data exist on the prevalence of HIV in this community. In 2008, we conducted a study to assess the presence of HIV infection among 477 immigrants in a town to the northeast of Tehran using a rapid test in the field. HIV prevalence was 0.2% (95% CI 0.005-1.2) with one person HIV-positive. We recommend periodic HIV sero-surveillance with detailed behavioral measures for this population in the future.