In order to make a comparison between the species of the Simuliidae family present in the east cordillera (east slope vs west slope) and characterize the simuliids from cold, medium and hot climates, the simuliid group of the ICN-MHN collected them in the departments of Cundinamarca and Tolima during the years 1992 to 1995. The region has 23 species from the genus Simulium (8 subgenera) and 15 species from the genus Gigantodax (5 groups). 14 species are endemic species. In order to make the species distribution analyses by similarity and paleoecology we use 70 collection locaalities grouped in 28 regions. The cladograms of the Simulium subgenus and Gigantodax groups were used. In the similarity analyses there are four major groups. There is only one zone of endemism, delimited by the presence of two species of the Gigantodax cormonsi group. The Paleoecology analyses indicates an altitudinal gradient independent of the mountain range and slope, with the low elevations corresponding to older regions and having the more primitive species.