Sofosbuvir (SOF) is a nonstructural 5B polymerase inhibitor with activity in all hepatitis C virus (HCV) genotypes and is the backbone of many anti‐HCV drug regimens. SOF is converted into inactive metabolites that undergo renal excretion. Patients with an estimated glomerular filtration rate (eGFR) < 30 mL/minute/1.73 m2 may experience increased drug exposure and thus potential toxicities along with decreased efficacy due to dose reduction or drug discontinuation. This is a single‐center study evaluating safety and effectiveness of SOF‐based regimens in patients with severe renal dysfunction, defined as eGFR <30 mL/minute/1.73 m2, including those receiving concurrent hemodialysis. Data were collected from patients with HCV and severe renal dysfunction who started full‐dose (400 mg) SOF‐based antiviral therapy ± ribavirin between April 2014 and February 2016. Medical records were reviewed for demographics, medical history, laboratory, radiologic imaging, echocardiography, transplant status, and liver pathologic findings. Twenty‐nine patients were identified; 12 had cirrhosis and 4 of those had decompensated cirrhosis. Fourteen patients had undergone transplantation of liver and/or kidney and were on calcineurin inhibitors, with 42% requiring dose increases or decreases while on therapy. All patients attained viral suppression on treatment, and 97% had a sustained viral response at 12 weeks posttreatment. There were no early treatment discontinuations. One death occurred posttreatment from a non‐ST elevation myocardial infarction in a patient with a history of coronary artery disease and ischemic cardiomyopathy. Conclusion: SOF‐based regimens appear safe in a broad range of patients with severe renal dysfunction, including those with decompensated cirrhosis and liver transplant. To confirm these retrospective findings, prospective studies that include SOF and SOF metabolite measurements coupled with prospective serial monitoring of electrocardiograms and echocardiograms are needed. (Hepatology Communications 2017;1:248‐255)