Preoperative alpha-L-fucosidase (AFU) has been used as a diagnostic biomarker for hepatocellular carcinoma (HCC), but its role as a prognostic predictor after partial hepatectomy has not been well defined. The study aimed to investigate the prognostic significance of preoperative serum AFU for HCC patients after hepatic resection.A retrospective training data set and a prospective validation data set were used to evaluate the prognosis of HCC after partial hepatectomy. A total of 669 patients with histopathologically confirmed HCC were enrolled. Univariate and multivariate analyses were used to identify the prognostic significance of preoperative serum AFU.The retrospective training data set showed a preoperative AFU>35 u l(-1) should be used. The prospective validation data set showed preoperative AFU was an independent prognostic factor of overall survival (OS) (P=0.008; hazard ratio: 2.333; 95% confidence interval: 1.249-4.369). Patients with a preoperative AFU>35 u l(-1) had a lower recurrence-free survival rate and an OS rate than those with AFU≤35 u l(-1), and they have a higher tendency to form macrovascular invasion. Furthermore, the prognostic significance of AFU>35 u l(-1) could also be applied to patients with alpha-fetoprotein levels of ≤400 ng ml(-1).Preoperative serum AFU is a prognostic predictor of HCC.