The first occurrence of the armored catfishes of the subfamily Callichthynae is reported in subterranean water bodies of northern and northeastern Brazil. The records include 3 species, each occurring in 1 of the 3 caves in the central and northeastern regions of Brazil: Callichthys callichthys from Casa do Caboclo cave, Sergipe state; Hoplosternum littorale from the Gruna da Lagoa do Meio, Bahia state; and Megalechis thoracata, from Casa de Pedra cave, Tocantins state.