During 2003 -2004, seventy-two samples were collected from 6 sampling points on Isparta stream basin (Isparta/Turkey). Macrozoobenthic organisms and physico-chemical parameters were investigated to assess the impact of the pollution on macrozoobenthos assemblages. Ecological methodologies (species richness, diversity and family biotic indices and multivariate analysis) were employed to assess the impact of the pollution on macrozoobenthic assemblages. During the study, totally 27293 specimens were collected from six sampling points. These belonged to 83 taxa distributed into 6 taxonomic groups as follows: Plathelminthes, Mollusca, Annelida, Crustacea, Insecta, and Arachnida. Biological oxygen demand, NH4-N, NO3-N, NO2-N SO4, conductivity, total hardness and turbidity parameters were measured higher in the 3rd and 6th sampling points, while dissolved oxygen amount was the lowest in these. pH was variable. In this study, the number of species is the highest at station 1, which is also reflected by Margalef and Shannon-Weaver indices. As the amount of pollution is higher at stations 3 and 6, the number of species is fewer in these stations compared to the others. Sampling points 1, 2, 4 and 5 were of good water quality levels. Changes in water quality levels were better reflected by species richness, diversity indices and principal component analysis than pollution indices in Isparta stream