Los autores han viajado por los Andes (1965) y los Alpes (1966) a fin de tener una idea conjunta de &Iacute;ndole geotect&oacute;nica que permita brindar los resultados de una comparaci&oacute;n reciente sobre la organizaci&oacute;n y desarrollo de ambas estructuras.<br /> Los Alpes se adec&uacute;an al r&eacute;gimen ortogeosinclinal cl&aacute;sico por su evoluci&oacute;n y magmatismo. Los Andes en la Argentina central y Chile, vecino, aparecen como un marginal ambiente liminar (Argand), pericrat&oacute;nico.<br /> Una afinidad es evidente entre ambas cadenas especialmente en lo que concierne a la deformaci&oacute;n pliocuaternaria que afectara a las mismas con la formaci&oacute;n de cuencas falladas rellenadas con series terr&iacute;genas potentes.<br /> Son analizados los aspectos estructurales de la regi&oacute;n andina de Mendoza y Neuqu&eacute;n correspondiente a la Cordillera Principal y expuestos los caracteres salientes de su tect&oacute;nica de z&oacute;calo con sistemas de fallas en compresi&oacute;n (Pale&oacute;geno-Mioceno) y sistemas similares en extensi&oacute;n (Plio-Cuaternario). Una r&aacute;pida visi&oacute;n de la estratigraf&iacute;a sirvi&oacute; de base a la exposici&oacute;n tect&oacute;nica.<br /> Fueron se&ntilde;alados los rasgos geol&oacute;gicos de la Precordillera, Cordillera Frontal y Cordillera Costanera de Chile que se asocian al substratum de la Cordillera Principal.<br /> Se analizan en el trabajo paralelamente algunos caracteres paleogeogr&aacute;ficos que interesan para la historia del continente sudamericano.The present authors have visited the Andes (19651 and the Alps (1966), in search of the geotectonical data necessary for the comparison of the evolution and development of these structures.<br /> Taking into account the evolution and magmatiam, the Alps pertain to the classical orthogeosyncline regime. While the Andes, in central Argentina and neighbouring Chile appear as a pericratonic, marginal, liminal environment (Argand). These two mountain chains show certain ressemblances, especially concerning the plio-quaternary deformation that effected both with the development of fault basins filled with thick terri- genus series.<br /> A structural analysis has been made in the Andean regi&oacute;n of Mendoza and Neuquen which belongs to the Cordillera Principal and the salient features, regarding the substratum&rsquo;s tectonic with its corresponding com- pression (Paleogene-Miocene) and extensi&oacute;n (Plio-Cuaternario) fault Systems, are put forward. The tectonic exposition is based on a rapid strati- graphical observation.<br /> The geological features that associate the Precordillera, Cordillera Frontal and Cordillera Costanera with the substratum of the Cordillera Principal, are pointed out.<br /> This paper also deais with certain paleogeographical aspects that are important for the Southamerican continent&rsquo;s history.