BACKGROUND: Suicide is a critical issue among opioid users. The aim of this study was to assess the relationship between HCV status and suicidal risk in patients receiving methadone treatment. METHODS: We used data from Methaville, a multicenter, pragmatic randomized trial designed to evaluate the feasibility of methadone induction in primary care compared with induction in specialized centers. Suicidal risk was assessed at enrollment and after one year of methadone treatment using the suicidality module in the MINI International Neuropsychiatric Interview. Socio-demographic characteristics, drug and alcohol consumption, behavioral and personality factors, history of drug use and health indicators were also assessed. RESULTS: A total of 195 individuals were enrolled from January 2009 to December 2010. Suicidal risk assessment was available at month 0 (M0) and M12 for 159 (72%) and 118 (73%) individuals, respectively. Forty-four (28%) were at risk of suicide at M0 and 17 (14%) at M12 (p=0.004). One patient attempted suicide by overdose during the one-year follow-up. The following three factors were associated with suicidal risk: hepatitis C virus (HCV) positive status (OR [95%CI]=17.25 [1.14-161.07]; p=0.04), receiving food assistance (OR [95%CI]=0.05 [0.00-1.05]; p=0.05) and a higher number of health problems (OR [95%CI]=1.24 [1.08-1.44]; p=0.003). CONCLUSIONS: Special attention should be given to HCV-positive patients through suicidal risk prevention strategies and routine suicide assessment as part of a comprehensive approach to prevention and care for opioid users. Our results represent a new and powerful argument for the expansion of access to HCV treatment to drug users with chronic infection.