Аннотация:At present time application of bioindication method is restricted by poor development of formal procedures for interpreting bioindication in quality terms. Tested approaches to bioindication data interpretation referring to quality have been classified and arranged according to increasing their formalization degree for terrestrial, water and soil ecosystems. The existing methods of formal rearrangement of bioindication data is shown to be mainly based on: 1) expert quality estimation, 2) statistical treatment of numerous biotic indexes, 3) complex bioindication combining various system levels of bioindicators, 4) analysis of curves of dose-response relationship and 5) ecological modeling. For practical purposes complex bioindication method is considered to be adequate to definite identification of the status of impacted ecosystems. This method involves appropriate data formalization and consistent ecological interpretation for formal procedure.