摘要:A Water Quality Index (WQI) is a numeric expression used to evaluate the quality of water bodies and make it easier understood by managers. This paper aims to assess water quality of Drina River in Serbia for the 2004 – 2011 period. For this purpose authors applied: Serbian Water Quality Index (SWQI). WQI value is dimensionless, single number ranging from 0 to 100 (best quality) derived from numerous physical, chemical, biological and microbiological parameters. For the Drina River SWQI was mainly rated as excellent. This study shows a clear decrease in water quality during summer period. Additionaly, this study shows that water quality along Drina River decreases slightly downstream, but it still provides values that according to SWQI descriptive quality indicator have been defined as excellent (90–100). This methodology includes parameters for assessment of organic loading, but does not involve parameters of heavy metals concentration.