Environmental enrichment results in many modifications in the brain such as structural, behavioural, and biochemical changes. alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type receptors for excitatory amino acid glutamate are recently found to be involved in neuronal plasticity. In this study, we examined whether environmental enrichment modified the brain expression of mRNA for subunit composition of AMPA receptors in adult mice using the real-time quantitative PCR method and western blotting. Mice housed in enriched environments showed significantly higher levels of GluR2 and GluR4 subunits in the hippocampus compared to control mice. We concluded that environmental enrichment can change the expression of AMPA receptor subunits and thus might modify the potentials of brain plasticity.