The purpose of this article is to consider the health benefits that may be derived from access to legal services for drug users, sex workers, men who have sex with men (MSM), women who have sex with women (WSW), and transgender persons. These populations share not only the experience of facing criminal sanctions on a regular basis, but also a resulting heightened vulnerability to human immunodeficiency virus / acquired immune deficiency syndrome (HIV/AIDS), as HIV is transmitted through unprotected sex and syringe-sharing by injecting drug users. The legal and human rights challenges faced by these individuals are described, some experiences of legal service provision are cited, and some lessons are drawn from these experiences on the way in which legal services can contribute to health as well as fill a gap in access to justice.