BACKGROUND: New highly efficacious direct-acting antiviral (DAA) therapies are available to treat chronic hepatitis C viral (HCV) infection. Real-world, patient-centered data on harms and benefits associated with these therapies are needed. METHODS: PROP UP is a multi-center prospective observational study that plans to enroll 1600 patients starting treatment with recently-approved DAA regimens. Informed by extensive input from a HCV patient engagement group who prioritized outcomes most important to them, patient-reported outcomes will be characterized using surveys at five time points: Baseline (T1), treatment week 4 (T2), end of treatment (T3), 12weeks post-treatment (T4), 12months post-treatment (T5). OUTCOMES: (1) Changes in side effects, functioning, pre-existing conditions, and out-of-pocket costs during therapy (T1 vs T2/T3); (2) Medication adherence in relation to a history of mental health/substance abuse, treatment regimens, pill burden, reasons for missed doses, and cure rates; (3) Short term impact of cure on functioning and amelioration of symptoms (T1 vs T4); (4) Long-term treatment harms or benefits of cure on symptoms, side effects, pre-existing conditions, and functioning (T1 vs T5). Similarities between regimens will be examined where comparisons are appropriate and meaningful. CONCLUSION: PROP UP complements previous clinical trials by focusing on patient-reported outcomes in a representative sample of patients treated in clinical practice, by collaborating with a patient engagement group, by characterizing the experiences of vulnerable subgroups, and by investigating long-term harms and benefits of treatments. PROP UP is designed to provide novel and detailed information to support informed decision-making for patients and providers contemplating HCV treatment (PCORI CER-1408-20,660; NCT02601820).