Evaluation of the ecological state of the Taganrog bay is presented, using a number of characters: quantity, biomass, eutrophication index (INEK) for microplankton and quantity of the oligochaets, Biotic Coefficient and Biotic Index (AMBI) for zoobenthos. Spatial and temporal dynamics of the Taganrog bay ecosystem’s state is examined. Schemes of the studied characters’ distribution over the Taganrog bay’s area are given. Eutrophication, depression
and background zones are marked out. A conclusion is made that the state of the bay’s ecosystem has been regularly worsening during the research period.