The juvenile development of the freshwater crab Dilocarcinus pagei Stimpson, 1861 was studied under laboratory conditions, focusing on setae morphology. The ovigerous females were collected manually associated with water hyacinth at the Municipal Dam of Sao Jose do Rio Preto (Sao Paulo, Brazil). The specimens were raised in the laboratory under constant aeration, photoperiod (12: 12 h) and temperature (27 +/- 1 degrees C). Twelve juvenile stages were obtained with descriptions of the main morphological characters that allow their identification are presented. Fourteen types of setae were discovered: dentate, denticulate, serrulate, papposerrate, cuspidate, plumose, plumodenticulate, plumoserrulate, simple, pappose, brush, curved, nail and setules. The greatest diversity of setae was found on the mouth appendages, especially the maxillule. The gill ontogeny and sexual dimorphism becomes apparent from the second juvenile stage onwards. At the third juvenile stage, the carapace begins to exhibit a wider shape, becoming similar to that of the adults.Univ Fed Rio Grande, Inst Oceanog, Lab Crustaceos Decapodos, BR-96201900 Rio Grande, RS, BrazilUniv Fed Rio Grande, Inst Ciencias Biol, Lab Zool Crustacea Decapoda, BR-96201900 Rio Grande, RS, BrazilUniv Estadual Paulista UNESP, Grp Pesquisa Biol Crustaceos CRUSTA, Lab Biol Crustaceos, BR-11330900 Sao Vicente, SP, BrazilUniv Estadual Paulista UNESP, Grp Pesquisa Biol Crustaceos CRUSTA, Lab Biol Crustaceos, BR-11330900 Sao Vicente, SP, Brazil