Glutamate receptors mediate the majority of excitatory responses in the central nervous system (CNS). Neurons express multiple subtypes and subunits of glutamate receptors, which are differentially distributed at pre- and postsynaptic sites. This allows the cell to respond differentially depending on the subunit composition of receptors at the postsynaptic membrane. The process by which receptors are targeted selectively to the appropriate synapse is poorly understood. Evidence exists that targeting of glutamate receptors to the different neuronal compartments is regulated at multiple levels involving a general targeting step; a local step where receptor-containing organelles are moved to the synapse; and a step where the receptors are stabilized at the synapse, which may involve interaction with an anchoring protein.