Comparative study on the spermatogenesis of two kinds of Korean planarias, Dugesia japonica and Phagocata vivida, were studied with light and electron microscope. Observation results were as follows. Except following details, fine structure and morphogenesis of the spermatogonia, primary spermatocyte, secondary spermatocyt spermatid and spermatozoon were consistant between the two species. The nucleus of primary spermatocyte of Dugesia japonica was surrounded with 36-38 microtubules, while that of Phagocata vivida with 40-42 microtubules. The C-shaped lamellar Golgi complex appeared in the spermatid cytoplasm of the former, while Straight-shaped lamellar Golgi complex in that of the latter. The four white spots were observed only in the nucleoplasm of matured spermatozoon in the latter, not in the former.