The identification and characterization of RNA binding proteins in Trypanosoma cruzi are particularly relevant as they play key roles in the regulatory mechanisms of gene expression. In this work, we have identified coding sequences for the proteins, named TcRRM1 and TcRRM2, in the EST database generated by the T. cruzi genomic initiative. TcRRM1 and TcRRM2 contain two RNA binding domains (RRM) and are very similar to two Trypanosoma brucei RNA binding proteins previously reported, Tbp34 and Tbp37, and to a not yet annotated ORF in Leishmania major genome project. The T cruzi RRM genes are organized in tandem, alternating with copies of Tcp28, a gene of unknown function. However, TcRRM transcript accumulation is higher in the spheromastigote stage, while Tcp28 transcripts accumulate more in the trypomastigote stage suggesting developmental regulation. (C) 2004 Elsevier Inc. All rights reserved.