In the dorsal lateral geniculate nucleus (dLGN), retinogeniculate (RG) synapses undergo strengthening and massive elimination during postnatal development. At the late developmental stage after postnatal day 20 (P20), visual experience plays an important role in maintenance of once established RG synapses since one week of visual deprivation from P20 triggered remodeling of RG connection patterns. Although molecular basis of RG synapse formation and elimination has been well studied, that of experience-dependent maintenance remained mostly unknown. We found that expression of type 1 metabotropic glutamate receptor (mGluR1) in the dLGN gradually increased after eye-opening (P15) and reached a plateau by P20. We therefore hypothesized that mGluR1 in the dLGN played an important role in the maintenance mechanism. In mGluR1 knockout (KO) mice, the developmental elimination of surplus RG synapses was completed normally by the third postnatal week. Consistent with developmental increment of mGluR1 expression, RG synapses were remodeled in mGluR1-KO mice older than P28 under normal rearing condition. In contrast, the KO mice lacked visual deprivation-induced remodeling of RG synapses. Importantly, blockade of mGluR1 in the dLGN during the late developmental stage triggered remodeling of RG synapses in wild-type mice. These results suggest that mGluR1 underlies the sensory experience-dependent maintenance to conserve precise RG connections in the dLGN.