The flagellated protozoan Trypanosoma cruzi is the etiological agent of Chagas disease. This is a widespread and important disease in Latin America, where about  18-20 million people are infected and no vaccine and effective chemotherapeutic agent against the parasite are available. T. cruzi strains represent subspecies based on intrinsic characteristics such as antigenic composition, morphology, isoenzyme patterns and the genomic profiles of DNA kinetoplast and host-parasite relationship. According to the diversity presented by T. cruzi,  strains are classified into two major groups T. cruzi I and II that correspond to specific zymodemes. The fact that gene expression in this parasite is regulated firstly at pos-transcriptional level, makes proteomic a promising tool for studying adaptative changes in these parasites. So, in this study, two dimensional gel electrophoresis was used to investigate differential protein expression in strains belonging to the same group T. cruzi I - Dm 28c and D7. Parasites were cultured in LIT medium at 28°C and 3x10⁹ cells were submitted to four  alternating freezing-thawing cycles in presence of PBS and protease inhibitor cocktail. Soluble proteins were precipitated by TCA and then solubilized in CHAPS, Urea, DTT and ampholytes. The experiments carried out in pH range 3-10, showed that most of spots in Dm 28c focused in the acid region of the gel. A considerable diversity as well as intensity of spots between Dm28c and D7, according to the gels analysis, were observed. When a narrow pH range 4-7 was applied, an increase number of spots was clearly resolved. The identification of differential proteins by mass spectrometry is in progress. These preliminary results show the reproducibility  obtained by comparing gels from different experiments using two distinct strains. Although the number of detected proteins represents only a small fraction of the whole set expressed by the parasite, we expect that further efforts on the proteomic analysis of T. cruzi will elucidate the biology of this parasite as well as the preferential association of T. cruzi strains to distinct hosts.