This article reports qualitative interview data from a study of participant-generated outcomes of two harm reduction programs in the United States. We address the question:"What does success in harm-reduction-based substance user treatment look like?" Providers in this study understood harm reduction to adhere to notions of "any positive change," client centeredness, and low-threshold services. Participants reported changes in demarginalization, engagement in the program, quality of life, social functioning, changes in substance use, and changes in future goals and plans. The nature of these changes is difficult to articulate within traditional notions of success (i.e., abstinence, program completion, etc.). We conclude that participants in harm reduction programs experience tangible positive changes but that legitimation of these changes calls for a reconceptualization of "outcomes" and "success" in the current context of substance user treatment and research.