PURPOSE: To ascertain the role played by the transforming growth factor (TGF)-beta superfamily in retinal development by determining the changes in the expression patterns of their receptors during development of the normal rat retina. METHODS: The expression of type I and type II receptors of the TGF-beta superfamily was observed at the protein level in rat eyes at embryonic age 17 days (E17), at birth (P0), at postnatal days 3, 6, 9, and at 11 weeks (P3, P6, P9, and adult, respectively). RESULTS: Activin type I receptor and BMP type IB receptor were first detected in P6 and P3 retinas, respectively, at the protein level, and activin type II receptor was first detected in the P0 retina. The other receptors (TGF-beta type I and II receptors, activin type IB receptor, BMP types IA and II receptors) were detected at E17. The period from P0 to P9 corresponded to the period of dynamic changes in the rat retinal development. CONCLUSION: The results suggest that the expression of TGF-beta superfamily is regulated along with retinal development and may be related to retinal development.