OBJECTIVE: To study the expression of transforming growth factor-β (TGF-β) and hepatocyte growth factor (HGF) in kidney tissues of children with primary focal segmental glomerular sclerosis (FSGS) and the possible role of the two growth factors in the development of FSGS. METHODS: Kidney specimens were obtained from 33 children with primary FSGS and 7 children with isolated haematuria but without FSGS (control group). Of the 33 children with primary FSGS, 6 children had no renal tubule interstitial pathological damage (Experimental I group) and 27 children had renal tubule interstitial pathological damage (Experimental II group). Expression of TGF-β and HGF in kidney tissues was ascertained by the immunohistochemical method. RESULTS: TGF-β and HGF were expressed in the three groups, but there were significant differences among the three groups. The expression of TGF-β and HGF in the two experiment groups increased significantly compared with that in the control group. The Experimental II group had increased TGF-β expression but a significantly decreased HGF expression compared with the Experimental I group. The index of tubule interstitial pathological changes was positively correlated with the TGF-β expression (r=0.763, P<0.01), but negatively correlated with the HGF expression (r=-0.461, P<0.05) in the Experimental II group. There was a negative correlation between TGF-β and HGF expression in children with primary FSGS (r=-0.425, P<0.05). CONCLUSIONS: The expression of TGF-β and HGF in kidney tissues is increased in children with primary FSGS. TGF-β might be a fibrogenic factor and HGF might be an anti-fibrotic factor in the kidney in primary FSGS.［Chin J Contemp Pediatr, 2010, 12 (8):630-633］