This chapter focuses on policy, practice, and research issues related to immigrant health because improving the health and well-being of the growing number of immigrants and refugees is an important goal for social workers in the health field. To further understand this special population, the chapter discusses: reasons for migrating, demographic characteristics of those who migrate, U.S. legal categories of migrants, as well as common misconceptions about migrants. It explains the policies that affect their use and barriers to use of the healthcare system. Policy and practice are closely connected in professional work with all clients but this is probably most true in work with immigrants where government and agency policies continually impact work with immigrant clients. The chapter concludes with a discussion of existing research on immigrants and healthcare, as well as areas that need further research.