In the last 20 years there was an increase in pollution of the middle section of the Revuca river and its main tributaries manifesting itself as the change of values of various ecological indexes. Changes of the species composition, the macrozoobenthos α-diversity and particularly of the fragmentation of the Perlidae (Plecoptera) family distribution were the most significant ones. The evaluation of food guilds and saprobic index had the smaller declarative value and the representation of various higher macrozoobenthos taxa had the smallest one. The occurrence of the Perla bipunctata (Perlidae: Plecoptera) endangered species has been recorded again in Slovakia after a lapse of 30 years.