In this study, the pollution level of the Poyrazlar Lake in Sakarya was determined by correlating the total coliform bacteria, fecal coliform bacteria, fecal streptococci, Escherichia coli and total viable value with physical and chemical parameters. Microbiological analysis were carried out using the spread plate method and the membrane filtration method. Microbiological pollution of the study area has been evaluated according to the Surface Water Quality Management Regulation (YSKYY). Total viable count between> 34.5 and <2747.5cfu/mL, E. coli between> 2.5 and <13 cfu/mL, fecal coliform bacteria count between> 6 and <24 cfu/mL, total coliform bacteria count> 28 and <287.7 cfu/mL and the number of fecal streptococcus bacteria was found to be between> 1 and <23.1 cfu/mL. The interrelations of the water of the physical parameters and the distribution of bacteria was evaluated statistically using SPSS 20.00. In the results obtained, a positive correlation coefficient of 0.829 between fecal coliform and total dissolved solids at p <0.05 level, and a negative correlation of -0.829 between electrical conductivity and temperature were determined. As a result of the statistical analysis, it was determined that there is a positive correlation with 0.886 between E. coli and the total living amount at the p <0.05 level. Microbiological pollution of the study area has been evaluated according to national and international criteria. When Poyrazlar Lake is evaluated according to the standards of Surface Water Quality Management Regulation, first class in terms of temperature, pH, total dissolved solids, electrical conductivity, fecal coliform was found to be second class in terms of total coliform and fourth class in terms of dissolved oxygen. According to the results obtained from the research, it was determined that Poyrazlar Lake is not polluted in terms of microbiological quality but has values close to the pollution limit.