Karyotypes of the blind catfishPimelodella kroneifrom three different caves in the southwestern part of the State of São Paulo, Brazil, and of its presumed ancestorPimelodella transitoriawere examined. Chromosome number and formula, as well as C-banding pattern and NOR location were found to be the same in both species, supporting the hypothesis of a close relationship and even conspecificity ofP. kroneiandP. transitoria.