Abstract: An investigation by scanning electron microscopy was made on the eggs of parasitic helminths. The eggs were fractured by DMSO freezing etching method. The parasite species examined were Ascaris lumbricoides, Enterobius vermicularis, Gongylonema pul-chrum, Necator americanus, Ancylostama duodenale, Trichuris suis, Clonorchis sinensis,, Paragonimus westermani, Fasciolopsis buski, Fasciola hepatica, Schistosoma japonicum, Taenia solium, Taeniarhyrichus saginatus, Spirometra mansoni, and Macracanthorhynchus. hirudinaceus.The egg shell, protein layer, vitelline membrane and lipid layer varied with the species among nematodes. There is a layer of etching structure on the outer surface of the egg shell in some trematodes and cestodes. According to the thickness of the egg shell, the eggs can be divided into 3 types, i.e. (1) below 0.1 μm, including T. solium egg; (2)0.1-1μm, including the eggs of N. americanus, A. duodenale, E. vermicularis, C. sinensis and S. japonicum; (3)1.1-2 μm including fertilized eggs of A. lumbricoides, eggs of T. suis, G. pulchrum, F. buski, F. hepatica and Spirometra mansoni.The operculum at one end of the eggs in some trematodes and cestodes is a hatching area, through which the larva hatches out. It was found that in some nematodes a characteristic structure at one or both ends of the egg is also present which may also be regarded as the hatching area.The fine tubular system in the embryophore of T. soZiufn and T. saginatus possess; not only microtubes but also micro caverns. In the egg shell of E. vermicularis and S. japonicum, this system is composed of numerous single tubules. In N. americanus egg,, however, only numerous holes are present.