Hepatitis C virus (HCV) infection affects between 150,000 to 300,000 human immunodeficiency (HIV) positive adults in the US (Alter et al., 1999; Sherman, Rouster, Chung, & Rajicic, 2002). The majority of co-infected adults (50%-90%) have acquired HCV through substance abuse (Centers for Disease Control [CDC], 1998; CDC, 2006b). A patient's decision to begin HCV treatment is not straightforward. HCV evaluation and treatment involves a significant amount of time, energy, effort, and compliance on the part of the patient. There is limited information on how adults with HCV mono-infection make decisions about HCV evaluation and treatment (Fraenkel, McGraw, Wongcharatraee, & Garcia-Tsao, 2005). Even less is known about how adults with HIV/HCV co-infection with a history of substance abuse make treatment decisions. The purpose of this study was to describe substance abuse experiences and to explore how these related to patient decision-making about HCV treatment in HIV/HCV co-infected adults. Qualitative descriptive design and secondary data analysis were used to study these phenomena. Data were managed by using NVivo software and analyzed by secondary data analysis and qualitative content analysis. Five major themes with sub-themes emerged during the data analysis. They were: (1) The Evolution of Substance Abuse (with sub-themes: substance abuse initiation, escalation, polysubstance abuse, normalcy: a family of addicts, the enemy within, and transmission and disclosure), (2) Revolving Door: Going Back Out (with sub-themes: specific events as a trigger, emotions as a trigger, alcohol as a trigger, and destructive relationships as a trigger), and (3) Reconstructing Life (with sub-themes: defining moments in substance abuse addiction and maintaining sobriety), (4) HCV Infection Treatment Issues (with sub-themes: HCV treatment: not a priority, fear, and misinformation, and desire to use stimulated during HCV treatment), and (5) Get Clean and Try It. The participants spoke about how their substance abuse evolved from inception to sobriety, and for some it remained a problem. Relapse and recovery were fragile in nature especially in these adults with HIV/HCV co-infection. The decision-making process is influenced by substance abuse experiences, however more research is needed to uncover specific factors influencing these decisions.