Dimilin, also known as diflubenzuron, is a benzoylphenyl urea compound that functions as an effective insecticide preventing the growth of chitin-containing organisms. Its main mode of action results in the inhibition of chitin deposition which leads to the death of the molting insect, such as the gypsy moth, Lymantria dispar L. The method of HPLC, high-pressure liquid chromatography, was chosen to assay for Dimilin because of its ability to accurately and gently separate a great variety of molecules by size, adsorption, reverse phase, or ion exchange. There are many variables that may affect a final result such as column type, solvent, pump rate, solvent ratio, and detector type. This study will investigate the action, fate, and overall effect of Dimilin in the environment with existing scientific literature and attempt to assay for the chemical via the HPLC method.