Objective To determine the concentration of hepatocyte growth factor (HGF) in vitreous of diabetic retinopathy (DR) and investigate the result and influence of HGF in neovascularization in proliferative diabetic retinopathy (PDR). Methods The high sensitive sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure the level of HGF in vitreous of normal group for 10 eyes, simple DR group for 7 eyes, PDR without iridal neovascularization group for 24 eyes, PDR with neovascularization of iris group in 9 eyes, other retinopathy group associated with neovascularization for 8 eyes. Results The mean value of HGF level in vitreous of the former groups was: (3.3 ±1.9) μg／L in normal group; (4.8±2.5) μg／L in simple DR group; (13.0 ±5.2) μg／L in PDR without iridal neovascularization group; (18.6±7.2) μg／L in PDR with neovascularization of iris group；(12.1±8.9) μg／L in other retinopathy associated with neovascularization group. Stastistics showed that HGF level in PDR group and other retinal diseases associated with neovascularization were significantly higher than that in normal group (P＜0.01), PDR with neovascularization of iris group showed a higher mean vitreous HGF concentration than those in PDR without iridal neovascularization and simple DR group (P＜0.05 or P＜0.01). Conclusion Our results indicate that vitreous HGF may play an important role in retinal neovascularization in PDR and other retinal diseases. (Chin J Ocul Fundus Dis, 2002, 18: 131-133)