mRNA of κ opioid receptor (KOR) can be transported to nerve fibers, including axons of dorsal root ganglia (DRG), and can be locally translated. Yeast three-hybrid screening identifies Copb1 as akormRNA-associated protein that form complexes with endogenouskormRNA, which are colocalized in the soma and axons of DRG neurons. Axonal transport ofkormRNA is demonstrated, directly, by observing mobilization of biotin-labeledkormRNA in Campenot chambers. Efficient transport ofkormRNA into the side chamber requires Copb1 and can be blocked by a drug that disrupts microtubules. The requirement for Copb1 in mobilizingkormRNA is confirmed by using the MS2–GFP mRNA-tagging system. Furthermore, Copb1 also facilitates the translation ofkormRNA in the soma and axons. This study provides evidence for a microtubule-dependent, active axonalkormRNA-transport process that involves Copb1 and can stimulate localized translation and suggests coupling of transport and translation of mRNAs destined to the remote areas such as axons.