In light of current initiatives to increase hepatitis C treatment uptake amongst current and former injectors, this article aims to explore the barriers and facilitators to treatment uptake from the patient's perspective. Semistructured interviews were conducted with people living with hepatitis C in Auckland, New Zealand and Sydney, Australia in 2004 and 2006. This article explores in detail one significant issue that has not so far been addressed in the social research literature about decision making for hepatitis C treatment. This is the concern expressed by a quarter of the 34 ex-injecting participants regarding the potential for hepatitis C treatment to cause a relapse to injecting drug use. The connection between hepatitis C treatment and relapse to injecting drug use is supported by a substantial clinical literature. Thus the proposed expansion of hepatitis C treatment into alcohol and other drug settings needs to be undertaken with caution. [PUBLICATION ABSTRACT]