The reservoirs Ogosta, Zhrebchevo and Koprinka were studied in the period 2009-2011. The Secchi Disk transparency and amount of chlorophyll-a were used for the assessment of the trophic state in the reservoirs. The structure and functioning of the trophic web and trophic integrity were analysed based on the composition of phytoplankton, benthic macroinvertebrate and fish communities. The trophic state of the three reservoirs was determined as mesotrophic. In the reservoirs, infested by Dreissena spp. (Ogosta and Zhrebchevo), the macrozoobenthic communities were represented mostly by filter feeders and deposit feeders. The fish fauna was predominated by benthivorous, followed by omnivorous species. In the noninfested reservoir Koprinka, the benthic community was composed mostly of deposit feeders, while the ichthyofauna was diverse in the trophic aspect. All reservoirs showed good trophic integrity.