Aims: To assess the concentration of atrazine in Lake Oconee and develop a qPCR assay as a potential marker for the presence of atrazine-degrading bacteria indicating atrazine contamination. Methods and Results: Water and sediment samples were collected from the Oconee Lake at four golf course sites, two residential sites, one cattle farming site and a forested site. Atrazine concentration at the study sites was determined using an ELISA kit and indicated the presence of atrazine from 0.72 ppb at the forested sites to 1.84 ppb at the golf course sites. QPCR results indicate the presence of atzA gene (atrazine chlorohydrolase) from 1.51 x 10(2) gene copies at the residential sites to 3.31 x 10(5) gene copies per 100 ml of water at the golf course regions of the lake and correlated (r = 0.64) with atrazine concentration. Sediment samples had higher atzA gene copies compared with the water samples (P < 0.05). Conclusions: Atrazine concentration and the highest quantity of atzA gene were detected in the golf course regions of the lake. Overall, atrazine concentration monitored in Lake Oconee was below the Environment Protection Agency (EPA) regulatory standards. Significance and Impact of the Study: Quantitative PCR is an efficient technique for assessing the presence of atrazine catabolism gene as a functional marker for atrazine-degrading bacteria and the presence of atrazine contamination.