133 p. Recurso Electr?nicoTrypanosoma rangeli es un par?sito protozoario que hasta ahora es considerado inocuo para el hospedero vertebrado pero perjudicial para el vector. Estudios han revelado que sus subpoblaciones son transmitidas selectivamente por las especies del g?nero Rhodnius, asimismo, se han descrito diferencias en la sensibilidad de los epimastigotes cortos y largos a la lisis mediada por la hemolinfa de R. prolixus. Debido a esto, se considera que existen factores proteicos en el par?sito que podr?an estar involucrados en dicha susceptibilidad o resistencia. Por esta raz?n, el objetivo del presente trabajo fue analizar los perfiles electrofor?ticos unidimensionales y bidimensionales de las prote?nas expresadas por los epimastigotes cortos y largos de las subpoblaciones KP1(+) y KP1(-) de T. rangeli. Se usaron las cepas Choach? (KP1+/A) y Rcol 0201 (KP1-/C); estas se masificaron durante 7 y 14 d?as para obtener epimastigotes cortos y largos respectivamente. Posteriormente fueron lisados y la prote?na fue cuantificada por el m?todo Bradford. La electroforesis por SDS-PAGE se realiz? en geles al 12%, mientras que la separaci?n bidimensional se realiz? por isoelectroenfoque y una posterior SDS-PAGE. Los geles unidimensionales fueron analizados con los programas Image Lab?, RAPDplot y PHYLIP96 y los geles bidimensionales con PDQuest? Advanced. Los perfiles unidimensionales mostraron que la mayor?a de prote?nas poseen un peso molecular entre 20-70 kDa. Los dendrogramas basados en an?lisis de identidad exhibieron diferencias entre las subpoblaciones y entre epimastigotes cortos y largos. Los perfiles bidimensionales mostraron spots exclusivos para cada una de las muestras que podr?an estar involucrados con la interacci?n par?sito-vector. Palabras clave: T. rangeli, SDS-PAGE, electroforesis bidimensional, prote?na, epimastigotesTrypanosoma rangeli is a protozoan parasite that to date it is considered an innocuous parasite for the vertebrate host but detrimental for the vector. Studies have revealed that its subpopulations are selectively transmitted by species of the genus Rhodnius, likewise, differences in the sensitivity of short and long epimastigotes to lysis mediated by hemolymph of R. prolixus have been described. Because of this, it is considered that there are protein factors in the parasite that could be involved in such susceptibility or resistance. Because of this, the aim of this work was to analyze the one - dimensional and two - dimensional electrophoretic profiles of the proteins expressed by short and long epimastigotes of the KP1 (+) and KP1 (-) subpopulations of T. rangeli. Choach? (KP1 + / A) and Rcol 0201 (KP1- / C) strains were used; these were massified for 7 and 14 days to obtain short and long epimastigotes respectively. They were subsequently lysed and the protein was quantified by the Bradford method. SDS-PAGE electrophoresis was performed on 12% gels, while the twodimensional separation was performed by isoelectric focusing and a subsequent SDS-PAGE. One-dimensional gels were analyzed with the Image Lab ?, RAPDplot and PHYLIP96 software packages and the two-dimensional gels with PDQuest ? Advanced software. The one-dimensional profiles showed that most proteins have a molecular weight between 20-70 kDa. Dendrograms based on identity analysis exhibited differences between subpopulations and between short and long epimastigotes. The two-dimensional profiles showed unique spots for each sample that might be involved with the parasite-vector interaction. Keywords: T. rangeli, SDS-PAGE, two-dimensional electrophoresis, proteins, epimastigotes.