OBJECTIVES: We studied the influence of absolute and relative contraindications on likelihood of treatment with dual-therapy for chronic heptatis C (HCV) infection in a national cohort of HCV-infected veterans. METHODS: We identified patients with an HCV diagnosis and either laboratory confirmation or a second diagnosis within a year. We excluded those with no encounters at least 6 months before the first diagnosis to ensure treatment naiveté. Cox Proportional Hazards regression models were developed with contraindications as time-varying exposures to assess their influence on treatment likelihood.  RESULTS: Of 318,814 previously untreated veterans diagnosed from 2004-2009, 101,444 (31.8%) met all criteria. Mean (SD) age was 58.6 (8.2) years and 96.7% were male. Race was known in 51.9%; of which most were white (49.9%) or black (40.4%). At diagnosis, most patients had unknown genotype (56.4%) or genotype 1 (35.3%). Contraindications were present at diagnosis in 17.2% of patients and 30.1% developed contraindications during follow-up. Predictive models revealed that several contraindications were significantly and independently associated with a decreased likelihood of treatment including kidney transplant (hazards ratio [HR]=0.29), thrombocytopenia (HR=0.38), acute myocardial infarction (HR=0.43), iron-deficiency anemia (HR=0.46), acute coronary syndromes (HR=0.62), bipolar disorder (HR=0.63), hepatic decompensation (HR=0.70), and retinopathy (HR=0.74). Patients with a liver transplant were much more likely to receive treatment (HR=3.51). Contraindications that had no influence on the likelihood of treatment were intractable epilepsy, pregnancy, major depression, and hemoglobinopathies. Neutropenia, auto-immune hepatitis, and other organ transplant had too few events and so were dropped from the models. CONCLUSIONS: This study provides evidence that clinicians make real-world treatment decisions for HCV based on some contraindications but not all. Future work should examine the occurrence of adverse events or treatment failure in contraindicated patients and explore ways to improve clinician awareness of contraindications when making treatment decisions.