Electrochemical reduction behaviour of Pyrifenox has been studied using d.c. polarography, cyclic voltammetry, a.c. polarography and differential pulse polarography in Britton-Robinson buffer ranging from pH 2.0 to 12.0. Pyrifenox is found to be reduced in a single reduction process and is attributed to the facile four electron reduction of azomethine group (>C=N-). Quantitative determination is carried out in the concentration range 1.0×10-5 M to 2.2×10-8 M. Kinetic parameters such as diffusion co-efficient (D) and forward rate constant (Ko f,h) values are evaluated and reduction mechanism is proposed. The result indicates that the process of the compound is irreversible and diffusion controlled. A simple and rapid differential pulse polarographic method has been developed for the determination of Pyrifenox in an agricultural formulations and environmental samples employing both calibration and standard addition methods.