Neotropical streams are understudied systems compared to their temperate counterparts, and little is known about the invertebrate communities that inhabit them or their trophic relationships. We examined diets of dominant macroinvertebrate taxa, representing all functional feeding groups, collected from sites along a continuum from upland headwaters to lowland stream reaches in central Panama. Gut contents of individual invertebrates were removed, slide mounted, identified and measured. Filter feeders from all sites were highly omnivorous. The degree of omnivory decreased along the continuum, with higher contributions of vascular plant detritus in upstream reaches. Diets of shredders were consistently dominated by plant detritus, but in upstream reaches they consumed relatively higher proportion of diatoms. As expected, predator guts contained mostly animal material, but omnivory in this group was relatively high in the upstream reaches and decreased with downstream distance. Diatoms were an appreciable component of predator diets in the upper sites.  Collector gatherers and scrapers showed no strong longitudinal patterns. Guts of all primary consumers collected in riffles contained a higher proportion of plant detritus than those from pools. Results indicate that omnivory is common among stream invertebrates in the Neotropics and that diets of most functional groups shift along stream continua.