Objective  To observe the expression of transforming growth factor-β2 （TGF-β2） in the vitreous body of patients with proliferative vitreoretinal diseases； to investigate the role of TGF-β2 in the pathogenesis of proliferative vitreoretinal diseases. Methods  In an experimental study， vitreous specimens were obtained during vitrectomy from 61 patients （61 eyes） with proliferative vitreoretinal diseases. The vitreous specimens were obtained from 37 eyes with proliferative diabetic retinopathy （PDR） and 24 eyes with proliferative vitreoretinopathy （PVR）. Eight vitreous fluid samples were obtained from a normal control group. The concentrations of TGF-β2 in the vitreous body were detected by enzyme-linked immunosorbent assay （ELISA）. Results  The concentrations of TGF-β2 in the vitreous bodies of eyes with PDR， PVR and the normal controls were 22.71±2.32 ng/ml， 21.28±1.7）ng/ml， and 19.00±0.62 ng/ml， respectively. Intravitreous concentrations of TGF-β2 were higher in patients with PDR and PVR than in the control group. The difference was statistically significant（F=7.756， P<0.01）. The concentration of TGF-β2 in the vitreous body from eyes of PDR patients was clearly higher than concentrations in PVR patients. The difference was statistically significant （P<0.05）. The concentrations of TGF-β2 in the vitreous body were higher in level Ⅵ of the PDR group in comparison to level Ⅴ of the PDR group. The difference was statistically significant （P<0.01）. The concentrations of TGF-β2 in the vitreous body were higher in the D class of the PVR group in comparison to the C class. The difference was statistically significant （P<0.01）. The concentrations of TGF-β2 in the vitreous bodies were positively correlated with the duration of the diseases： the correlation for the PDR group was r=0.705 （P<0.01） and the correlation for the PVR group was r=0.934（P<0.01）. Conclusion  TGF-β2 may play an important role in the pathogenesis and development of proliferative vitreoretinal diseases.