The ultrastructure of Sertoli cell in the testes of Korean native goats was investigated by scanning and transmission electron microscopy to elucidate the relationship between germ cell and Sertoli cell processes in the spermiogenetic cycle. Type-A Sertoli cells at stage V of the spermiogenetic cycle and type-B Sertoli cells at stage VII of the spermiogenetic cycle were used for analysis. Morphologically, the Sertoli cell processes were classified into sheet-like and slender cord-like processes. The sheet-like process originated solely from the Sertoli cell column while the slender cord-like process projected either from the Sertoli cell column or the sheet-like process. Periodic acid (PA)-thiocarbohydrazide (TCH)-silver protein (SP)-physical development (PD)-positive granules were found diffusively both in the sheet-like and slender cord-like processes near the round spermatid, whereas they had accumulated near the head of the elongated spermatid. The morphological variation and glucoconjugate histochemical reaction of the Sertoli cell processes reflect nourishment, movement and transformation of the spermatogenic cells in accordance with spermiogenesis.