Lake Uluabat is one of the most important shallow lakes in Turkey. The lake is located 15 km south of the Marmara Sea and 30 km west of the city of Bursa. The lake is very important in terms of biodiversity, but knowledge of its water quality is somewhat limited. The objective of this study was to assess water quality in Lake Uluabat and provide information for future management decisions. The temperature (T), pH, electrical conductivity (EC), dissolved oxygen (DO), alkalinity, chemical oxygen demand (COD), nitrogen species, phosphorus species, and chlorophyll-a (Chl-a) concentrations were monitored monthly at ten sampling points in the lake between August 2013 and July 2014. As a result, it was determined that the lake water has the characteristics of class 4 waters according to the Turkish Surface Water Quality Management Regulations (SWQMR). Also it was determined that Mustafakemalpaşa Brook carries significant amount of pollution loads into the lake. According to qualitative and quantitative observations, the effects of human impact and current status of the lake were determined. The physical and chemical characteristics of the lake water have changed according to human activities and nutrient loadings. According to the trophic level values and concentration values, the Lake exceeded the regulation limits.