Abstract: The spermatozoon of teleost Cyprinus carpio (Linnaeus) consisted of head,mid-piece and tail.The nucleus,within which there were some gaps,of the head was allipse.There were electron-dense materials in the gaps.The mid-piece,consisting of centriolar complex and sleeve,was connected to the posterior of the nucleus.The centriolar complex was in the implantation fossa which was at the posterior end of the nucleus.There were mitochondria and some vesicles in the sleeve.The vesicles were of two types:one contains some electron-dense materials,the other was electron transparent.The membrane which was parallel to the inner membrane of the sleeve could be seen within the cytoplasm of the sleeve.The tail was thin and long.It was connected with basal body and stretches out of the sleeve.At the proximal end of the tail there were many vesicles outside the axoneme.The vesicles were electron transparent.The distal end of the tail,however,did not contain any vesicles.