AIM: To investigate the differentiation of human umbilical cord blood (HUCB)-derived mesenchymal stem cells (MSCs) into hepatocytes by induction of fibroblast growth factor-4 (FGF-4) and hepatocyte growth factor (HGF), and to find a new source of cell types for therapies of hepatic diseases.METHODS: vSCs were isolated by combining gradient density centrifugation with plastic adherence. When HUCB-derived MSCs reached 70% confluence, they were cultured in Iscove modified Dulbecco medium (IMDM) supplemented with 10 mL/L FBS, 20 ng/mL HGF and 10 ng/mL FGF-4. The medium was changed every 4 d and stored for albumin, alpha-fetoprotein (AFP) and urea assay. Expression of CK-18 was detected by immunocytochemistry. Glycogen storage in hepatocytes was determined by PAS staining.RESULTS: By combining gradient density centrifugation with plastic adherence, we could isolate MSCs from 25.6% of human umbilical cord blood. When MSCs were cultured with FGF-4 and HGF, approximately 63.6% of cells became small, round and epithelioid on d 28 by morphology. Compared with the control, the level of AFP increased significantly from d 12 to 18.20±1.16 μg/L (t = 2.884, P＜0.05) in MSCs cultured with FGF-4 and HGF, and was higher (54.28±3.11 μg/L) on d 28 (t = 13.493, P＜0.01). Albumin increased significantly on d 16 (t = 6.68, P＜0.01) to 1.02±0.15 μg/mL, and to 3.63±0.30 μg/mL on d 28 (t = 11.748, P＜0.01). Urea(4.72±1.03 μmol/L) was detected on d 20 (t = 4.272,P＜0.01), and continued to increase to 10.28±1.06 μmol/L on d 28 (t = 9.276, P＜0.01). Cells expressed CK-18 on d 16. Glycogen storage was observed on d 24. CONCLUSION: HUCB-derived MSCs can differentiate into hepatocytes by induction of FGF-4 and HGF. HUCBderived MSCs are a new source of cell types for cell transplantation therapy of hepatic diseases.