Background: Extended hepatectomy may be required to provide the best chance for cure of hepatobiliary malignancies. However, the procedure may be associated with significant morbidity and mortality. Methods: We analyzed the outcome of 127 consecutive patients who underwent extended hepatectomy (resection of ≥ 5 liver segments) for hepatobiliary malignancies. Results: The patients underwent extended hepatectomy for colorectal metastases (n = 86; 67.7%), hepatocellular carcinoma (n = 12; 9.4%), cholangiocarcinoma (n = 14; 11.0%), and other malignant diseases (n = 15; 11.5%). Thirty-two left and ninety-five right extended hepatectomies were performed. Eight patients also underwent caudate lobe resection, and 40 patients underwent a synchronous intraabdominal procedure. Twenty patients underwent radiofrequency ablation, and 31 underwent preoperative portal vein embolization. The median blood loss was 300 mL for right hepatectomy and 600 mL for left hepatectomy (P = 0.02). Thirty-six patients (28.3%) received a blood transfusion. The overall complication rate was 30.7% (n = 39), and the operative mortality rate was 0.8% (n = 1). Significant liver insufficiency (total bilirubin level > 10 mg/dL or international normalized ratio > 2) occurred in 6 patients (4.7%). Multivariate analysis showed that a synchronous intraabdominal procedure was the only factor associated with an increased risk of morbidity (hazard ratio [HR], 4.9; P = 0.02). The median survival was 41.9 months. The overall 5-year survival rate was 25.5%. Conclusions: Extended hepatectomy can be performed with a near-zero operative mortality rate and is associated with long-term survival in a subset of patients with malignant hepatobiliary disease. Combining extended hepatectomy with another intraabdominal procedure increases the risk of postoperative morbidity.