In order to investigate the spermiogenesis and the structure of the Korean cattle spermatozoa, the tissue obtained from the testis and the epididymis of six matured bull were conventionary prepared as thin sections and these sections were observed under a transmission electron microscope. Based on the development of the various permanent organelles and certain transient structures, the spermiogenesis of the Korean cattle could be divided into four main phases: Golgi, cap, acrosome and maturation; and these phases had been further subdivided into a total of nine stages. In the maturation phase, the condensation of the nuclear karyoplasm had progressed from the upper side to the lower side of the nucleus as the movement of the nuclear ring which would be disappeared after maturation. The equatorial segment between the acrosome and the postacrosomal dense lamina of the head was not observed. The number of neck plates in the column, 18-30, seemd to be smaller than other reported animals.