The Sunda porcupine (Hystrix javanica) is an endemic species of Indonesia. The population of this species has been decreased by hunting and habitat loss. Understanding of reproductive characteristics is essential for the appropriate management of their population. However, there is little knowledge about reproductive features of this species. The epididymis and deferent duct are important organs for maturation, transport, and storage of sperm. In this study, therefore, the epididymis and deferent duct of Sunda porcupines were examined histologically, histochemically, immunohistochemically, and electron-microscopically to understand their structures and functions. Four adult wild porcupines that inhabit Central Java, Indonesia, were captured in June and September and euthanized. Then, the epididymides and deferent ducts were removed. Principal cells were the main cell type found in the epididymis with stereocilia and apical blebs, but both of these structures were absent in the deferent duct. These observations suggest high secretion and absorption capability by the epididymal epithelium. In the epididymis and deferent duct, PAS-positive principal cells were shown, and the immunoreactivities for 3β-HSD were found in the epithelium of the deferent ducts. These reults suggest effects on sperm by glycoproteins and steroid metabolites.