Two groups of three headwater streams located at aproximately 1700 and 2500 m.a.s.l. were chosen in the Otún watershed (Central Andes of Colombia) to determine the influence of altitude on the composition, biomass and feeding preferences of macroinvertebrates associated to leaf packs. Ten samples of leaf packs per stream were collected and macroinvertebrates identified and separated into functional feeding groups according to their gut content. A total of 4936 individuals belonging to 95 genera, 51 families and 17 orders were found. Total abundance and taxa richness were not affected by elevation but the number and biomass of shredders increased with altitude and taxa composition changed. Simulium (Diptera: Simuliidae) was the predominant taxa at lower elevation (46% of individuals) and Phylloicus (Trichoptera: Calamoceratidae) the most important at higher elevation (30.8% of individuals). However in terms of biomass Phylloicus, a generalist shredder, was the most important taxa at both elevations representing more than 36% of total biomass. Shredders represented 25% of abundance and 66% of biomass and increased significantly with elevation. The information reveals that there are not very specialized feeding groups, and that shredders (individuals with more than 50% of CPOM) are very important components of the benthic fauna in these tropical streams.