In this study, gold nanoparticles (AuNPs) were synthesized using sodium borohydride (NaBH4) as reductant. AuNPs size and shape were experimented by using various characterization techniques. The synthesized AuNPs performance capability for atrazine (ATR) detection, at a glassy carbon electrode (GCE), was verified using cyclic voltammetry (CV) as the determining mode. AuNPs impressive electrochemical performance and stability at the GCE led to further studies, without the need to apply nafion. ATR linear concentration plot ranged from 10 to 17 nM, with a lower limit of detection (LOD) of 0.17 nM, and a regression coefficient (R-2) of 0.9934, under optimized conditions. The proposed sensor was very reliable, with a relative standard deviation (RSD) of 1.1%, for n = 20, and it was quite sensitive for ATR, with no discernible interference from other ions. Consequently, AuNPs were effectively used to identify ATR in several pesticide industry wastewater samples.