Abstract This paper aims to present an assessment of Olt River water quality along Brasov county area, using data acquired during 2005- 2007. Olt River is an important river in Romania, and its basin is covering almost 10 counties, which main part of its middle section passes Brasov County. Olt River is providing water for industry, agriculture and human use, but is also collecting treated and not treated wastewaters from different sources. Two important sampling sites were studied: Feldioara and Hoghiz, representative for the Olt River water quality in Brasov County. For these two sampling sites a monitoring study was developed, considering the following representative water quality indicators: dissolved oxygen (DO), chemical oxygen demand (COD-Cr), ammonia. The quality assessment was based on the aggregated indicator, Global Pollution Index (GPI) method.