Spermiogenesis and spermatozoa of representatives of the genera Lebiasina and Piabucina are described. Spermiogenesis is quite similar among all analyzed species of these genera and is identified as Type II. In this type of spermiogenesis, the flagellum of earliest spermatids lies lateral to the nucleus. A slight movement of the nucleus towards the centriolar complex is observed. In late spermatids, the nucleus slightly elongates towards the flagellum. The formation of two striated rootlets apparently occurs in early/intermediate spermatids. The spermatozoa of species of Lebiasina and Piabucina share (1) a drop-shaped slightly elongated nucleus that is laterally positioned relative to the flagellum; (2) a superolateral centriolar complex; (3) two striated rootlets; (4) a basolateral midpiece; (5) oblong mitochondria and (6) a few spherical vesicles. The spermatic characteristics of Lebiasina and Piabucina indicate that spermiogenesis is a homologous process among all species of both genera examined to date and can be considered, along with the spermatozoa morphology, additional evidence indicating a close relationship between Lebiasina and Piabucina. © 2013 Sociedade Brasileira de Ictiologia.113573579Baicere-Silva, C.M., Benine, R.C., Quagio-Grassiotto, I., Markiana nigripinnis (Perugia, 1891) as a putative member of the subfamily Stevardiinae (Characiformes: Characidae): Spermatic evidence (2011) Neotropical Ichthyology, 9, pp. 371-376Baicere-Silva, C.M., Ferreira, K.M., Malabarba, L.R., Benine, R.C., Quagio-Grassiotto, I., Spermatic characteristics and sperm evolution on the subfamily Stevardiinae (Ostariophysi: Characiformes: Characidae) (2011) Neotropical Ichthyology, 9, pp. 377-392Burns, J.R., Quagio-Grassiotto, I., Jamieson, B.G.M., Ultrastructure of spermatozoa: Ostariophysi (2009) Reproductive Biology and Phylogeny of Fish (Agnatha and Osteichthyes), pp. 287-388. , In: Jamieson, B. G. M. (Ed.), Enfield, Science PublishersFerreira, K.M., Menezes, N.A., Quagio-Grassiotto, I., A new genus and two new species of Stevardiinae (Characiformes: Characidae) with a hypothesis on their relationships based on morphological and histological data (2011) Neotropical Ichthyology, 9, pp. 281-298Javonillo, R., Burns, J.R., Weitzman, S.H., Reproductive morphology of Brittanichthys axelrodi (Teleostei: Characidae), a miniature inseminating fish from South America (2007) Journal of Morphology, 268, pp. 23-32Matos, E., Matos, P., Corral, L., Azevedo, C., Estrutura fina do espermatozóide de Acestrorhynchus falcatus Bloch (Teleostei, Characidae) da região norte do Brasil (2000) Revista Brasileira De Zo-ologia, 17, pp. 747-751Mattei, X., Spermiogenése des poisson (1970) Comparative Spermatology, pp. 57-72. , In: Baccetti, B. (Ed.), New York, Academic PressNetto-Ferreira, A.L., (2010) Revisão Taxonômica E Relações Interespecíficas De Lebiasininae (Ostariophysi: Characiformes: Lebiasinidae), p. 443. , http://www.teses.usp.br/teses/disponiveis/41/41133/tde-02022011-165808/pt-br.php, Unpublished Ph.D. Dissertation, Universidade de São Paulo, São Paulo, Brazil, accessed 25 Jan 2013Netto-Ferreira, A.L., Three new species of Lebiasina (Characiformes: Lebiasinidae) from the Brazilian Shield border at Serra do Cachimbo, Pará, Brazil (2012) Neotropical Ichthyology, 10, pp. 487-498Netto-Ferreira, A.L., Oyakawa, O.T., Zuanon, J., Nolasco, J.C., Lebiasina yepezi, a new Lebiasininae (Characiformes: Lebiasinidae) from the Serra Parima-Tapirapecó mountains (2011) Neotropical Ichthyology, 9, pp. 767-775Oliveira, C.L.C., Burns, J.R., Malabarba, L.R., Weitzman, S.H., Sperm ultrastructure in the inseminating Macropsobrycon uruguayanae (Teleostei: Characidae: Cheirodontinae) (2008) Journal of Morphology, 269, pp. 691-697Quagio-Grassiotto, I., Oliveira, C., Sperm ultrastructure and a new type of spermiogenesis in two species of Pimelodidae, with a comparative review of sperm ultrastructure in Siluriformes (Teleostei: Ostariophysi) (2008) Zoologischer Anzeiger - a Journal of Comparative Zoology, 247, pp. 55-66Quagio-Grassioto, I., Malabarba, L.R., Azevedo, M.A., Burns, J.R., Baicere-Silva, C.M., Quevedo, R., (2012) Unique Derived Features In Spermiogenesis and Sperm Morphology Supporting a Close Relationship Between the Species of Hollandichthys and Rachoviscus (Characiformes: Characidae), pp. 609-625. , CopeiaSantana, J.C.O., Baicere-Silva, C.M., Gusmão-Pompiani, P., Benine, R.C., Quagio-Grassiotto, I., An assessment approach for application of spermatic data in phylogenetic analyses: Within the genus Moenkhausia Eigenmann 1903 (Characiformes: Characidae) (2013) Acta Zoologica (Stockholm), 94, pp. 335-354Weitzman, M., Weitzman, S.H., Family Lebiasinidae (2003) Check List of the Freshwater Fishes of South and Central America, pp. 241-250. , In: Reis, R. E., S. O. Kullander & C. J. Ferraris, Jr. (Eds.), Porto Alegre, Edipucrs