The ultrastructure of the spermatozoa of seven species of Proceratophrys and one of Odontophrynus was analyzed in the present study. The sperm of Odontophrynus juquinha is similar to that of Odontophrynus cultripes, previously described, and to those of Proceratophrys branti, Proceratophrys bigibbosa, Proceratophrys affinis concavitympanum, Proceratophrys huntingtoni, Proceratophrys conformis moratoi, P. moratoi, and Proceratophrys palustris, in relation to the acrosomal vesicle and the subacrosomal cone that covers the anterior region of the nucleus in the sperm head. We observed transverse striations in the midpiece of the Odontophrynus juquinha sperm, a feature not observed in any Proceratophrys species. The sperm tail of all the studied species had a simple flagella and single axoneme associated with auxiliary structures (juxta-axonemal + undulating membrane + axial fiber). However, the juxta-axonemal fiber is thicker and the undulating membrane is shorter in Proceratophrys in comparison with Odontophrynus. In addition to differentiating these two genera, these features represent a possible autapomorphy in Proceratophrys.