This is a multi-site national study (8 U.S. cities), where up to 1000 HCV-infected PWIDs (injecting illicit substances within the last 3 months) will be randomized to either PN plus biweekly blister pack dispensation versus mDOT. Among patients who go on to initiate HCV treatment (n=600 targeted) with a once-daily combination regimen, a comparison will be conducted of the proportion of patients in each arm who: (a) optimally adhere (>=80%), (b) complete treatment, (c) achieve SVR, and (d) develop resistance. The primary outcome will be SVR. The 8 sites offer geographic and policy diversity: New York City, Baltimore, Providence, Boston, Morgantown, Seattle, San Francisco, and Albuquerque.