Light deprivation is known to induce a significant decrease in the percentage of N-methyl-D- aspartate receptor 2A subunit (NR2A)-expressing neurons during development. The purpose of this study was to investigate the effects of binocular form deprivation (BFD) and chondroitin sulfate proteoglycan (CSPG) degradation on NR2A expression via an immunohistochemical study, around the end of a critical developmental period. The results show that the positive staining of NR2A in the normal rat visual cortex increases gradually from postnatal 3-5 weeks (P < 0.05), but the changes from 5 weeks to 7 weeks were not significant. The positive staining of NR2A following BFD in the rat visual cortex slightly increased from postnatal 3-7 weeks (P > 0.05). The positive staining of NR2A in the CSPG-treated group was insignificant compared with the BFD group at the same time point from 4 weeks to 7 weeks (P > 0.05). Thus, the effect of BFD on NR2A expression in the rat visual cortex was similar to that of CSPG degradation around the end of the critical developmental period.