We present the geographical and altitudinal distribution of the Gerridae family on the western slopes of the Western Cordillera of Andes in southwestern Colombia. The specimens were captured in different water bodies, eight sampling sites, during 2009 and 2010. Taxonomic composition was analyzed with respect to geographical and altitudinal range, biomes and the similarity between areas. The geographical distribution of the Gerridae is related to geographic area, foothills and Plain Pacific, altitudinal range (0-2000 masl) and features of type of biome. The communities of Gerridae from Pacific Plain are in the same Zonobioma but differ in taxonomic composition due to differences in water bodies and microhabitats own. On the other hand we show the inverse relationship between altitude and species richness.