To investigate the risk factors for postoperative liver insufficiency in patients with Child-Pugh class A liver function undergoing liver resection. A total of 427 consecutive patients undergoing partial hepatectomy from October 2007 to April 2011 at a single center (Department of Hepatic SurgeryI, Eastern Hepatobiliary Surgery Hospital, Shanghai, China) were included in the study. All the patients had preoperative liver function of Child-Pugh class A and were diagnosed as having primary liver cancer by postoperative histopathology. Surgery was performed by the same team and hepatic resection was carried out by a clamp crushing method. A clamp/unclamp time of 15 min/5 min was adopted for hepatic inflow occlusion. Patients' records of demographic variables, intraoperative parameters, pathological findings and laboratory test results were reviewed. Postoperative liver insufficiency and failure were defined as prolonged hyperbilirubinemia unrelated to biliary obstruction or leak, clinically apparent ascites, prolonged coagulopathy requiring frozen fresh plasma, and/or hepatic encephalopathy. The incidence of postoperative liver insufficiency or liver failure was observed and the attributing risk factors were analyzed. A multivariate analysis was conducted to determine the independent predictive factors. Among the 427 patients, there were 362 males and 65 females, with a mean age of 51.1 ± 10.4 years. Most patients (86.4%) had a background of viral hepatitis and 234 (54.8%) patients had liver cirrhosis. Indications for partial hepatectomy included hepatocellular carcinoma (391 patients), intrahepatic cholangiocarcinoma (31 patients) and a combination of both (5 patients). Hepatic resections of ≤ 3 and ≥ 4 liver segments were performed in 358 (83.8%) and 69 (16.2%) patients, respectively. Seventeen (4.0%) patients developed liver insufficiency after hepatectomy, of whom 10 patients manifested as prolonged hyperbilirubinemia unrelated to biliary obstruction or leak, 6 patients had clinically apparent ascites and prolonged coagulopathy, 1 patient had hepatic encephalopathy and died on day 21 after surgery. On univariate analysis, age ≥ 60 years and prealbumin < 170 mg/dL were found to be significantly correlated with postoperative liver insufficiency (P = 0.045 and P = 0.009, respectively). There was no statistical difference in postoperative liver insufficiency between patients with or without hepatitis, liver cirrhosis and esophagogastric varices. Intraoperative parameters (type of resection, inflow blood occlusion time, blood loss and blood transfusion) and laboratory test results were not associated with postoperative liver insufficiency either. Age ≥ 60 years and prealbumin < 170 mg/dL were selected on multivariate analysis, and only prealbumin < 170 mg/dL remained predictive (hazard ratio, 3.192; 95%CI: 1.185-8.601, P = 0.022). Prealbumin serum level is a predictive factor for postoperative liver insufficiency in patients with liver function of Child-Pugh class A undergoing hepatectomy. Since prealbumin is a good marker of nutritional status, the improved nutritional status may decrease the incidence of liver insufficiency.