The remnant liver after hepatectomy may have inadequate blood supply, especially following nonanatomical resection or vascular damage. To evaluate whether remnant liver ischemia (RLI) may have an adverse effect on long-term survival and morbidity after liver resection in patients with hepatocellular carcinoma. This study was a retrospective analysis at Seoul National University Bundang Hospital. Remnant liver ischemia was graded on postoperative computed tomographic scans in 328 patients who underwent hepatectomy for hepatocellular carcinoma between January 1, 2004, and December 31, 2013. Remnant liver ischemia was defined as reduced or absent contrast enhancement during the venous phase. Remnant liver ischemia was classified as minimal (none or marginal) or severe (partial, segmental, or necrotic). Among 328 patients (252 male and 76 female; age range, 26-83 years [mean age, 58.2 years]), radiologic signs of severe RLI were found in 98 patients (29.9%), of whom 63, 16, and 19 had partial, segmental, or necrotic RLI, respectively. These patients experienced more complications and longer hospital stay than patients with minimal RLI. Preoperative history of transarterial embolization (odds ratio [OR], 1.77; 95% CI, 1.02-3.03; P = .04), use of the Pringle maneuver (OR, 1.96; 95% CI, 1.08-3.58; P = .03), and longer operative time (OR, 1.003; 95% CI, 1.002-1.005; P < .001) were independent risk factors for severe RLI. Early recurrence rates within 6 (60.2% vs 9.6%) or 12 (79.6% vs 18.7%) months after hepatectomy were higher in patients with severe RLI than in patients without RLI (P < .001). Severe remnant liver ischemia was an independent risk factor for overall survival (OR, 6.98; 95% CI, 4.27-11.43; P < .001) and disease-free survival (OR, 5.15; 95% CI, 3.62-7.35; P < .001). Preventive management and technical refinements in hepatectomy are important to decrease the risk of RLI and to improve survival of patients with hepatocellular carcinoma.