We examined the subcellular distribution of specific mRNAs in cultured sympathetic neurons. Under appropriate conditions, sympathetic neurons extend both axons and dendrites that are distinguishable by light microscopic and immunocytochemical criteria. In situ hybridization revealed a differential localization of mRNA within dendrites. mRNA encoding MAP2 was abundant in cell bodies and distributed nonhomogeneously throughout the dendritic compartment, but was not detected in axons. In contrast, mRNAs encoding GAP-43 and alpha-tubulin were restricted to the cell body and largely excluded from dendrites as well as axons. Detergent extraction revealed that most dendrite-associated mRNA encoding MAP2 was associated with the Triton X-100 insoluble fraction of the cell. The subset of mRNAs present in the dendritic compartment may encode proteins involved in the morphogenesis and remodeling of dendrites.