Eight weeks duration of ledipasvir/sofosbuvir (LDV/SOF) can be considered in genotype 1 hepatitis C virus-infected patients who are treatment-naive, do not have cirrhosis, and have a pretreatment viral load <6,000,000 IU/mL. The effectiveness of this regimen, however, has not been fully confirmed by real-world experience. Using data from real-world cohorts, we aimed to determine the effectiveness of 8 weeks of LDV/SOF treatment, examine variables associated with relapse after treatment with this regimen, and compare the effectiveness of 8 weeks and 12 weeks of LDV/SOF treatment. To evaluate the effectiveness of 8 weeks of therapy and characteristics associated with relapse, we used individual patient data from the IFI (Institut für Interdisziplinäre Medizin), Burman's Pharmacy, and Kaiser Permanente Southern California. All patients had fibrosis staging assessed with biopsy, transient elastography, or serum biomarkers. We also performed a systematic review and meta-analysis of six additional real-world cohorts, to compare effectiveness of 8 weeks to 12 weeks duration. In our pooled data analysis, 634 patients were treated for 8 weeks with LDV/SOF, of whom all had outcomes of cure or relapse without loss to follow-up. Per protocol rates of sustained virologic response at 12 weeks were 98.1% (622/634) in the full cohort and 97.9% (571/583) among treatment-eligible patients. Exact logistic regression revealed no specific patient characteristics associated with relapse. Our meta-analysis of six additional real-world cohorts, comprised of 5,637 patients, demonstrated similar risk for relapse between 8 weeks and 12 weeks of LDV/SOF (relative risk = 0.99, 95% confidence interval 0.98-1.00).CONCLUSION: An 8-week duration of treatment with LDV/SOF is highly effective in properly selected patients; greater use of this regimen is recommended. (Hepatology 2017;65:1094-1103).