Synaptic function in the central nervous system (CNS) is highly dependent on a dynamic actin cytoskeleton in both the pre- and the postsynaptic compartment. Remodelling of the actin cytoskeleton is controlled by tropomyosins, a family of actin-associated proteins which define distinct actin filament populations. Here we show that TPM3 and TPM4 gene products localize to the postsynaptic region in mouse hippocampal neurons. Furthermore our data confirm previous findings of isoform segregation to the pre- and postsynaptic compartments at CNS synapses. These data provide fundamental insights in the formation of functionally distinct actin filament populations at the pre- and post-synapse.