The negative effects of discrimination on those who are stigmatized are well documented. What is less clear, however, is whether the source of the discrimination has differential outcomes on the person being discriminated against. Survey results from 685 injecting drug users (IDUs) revealed that IDUs who experienced discrimination from healthcare workers had poorer physical health, whereas physical health was unrelated to experiences of discrimination by those outside the healthcare system (family, friends, and partners). In contrast, IDUs' mental health status was less sensitive to the source of discrimination. Discrimination by healthcare workers and by others outside the healthcare industry were both related to IDUs' mental health. Implications and limitations of this research are discussed.