Sodium dimethyl phosphorothioate is an organophosphorus compound with the chemical formula C₂H₆NaO₂PS. It is the sodium salt of dimethyl phosphorothioic acid. This compound is a key intermediate in the synthesis of organophosphorus insecticides. Its primary industrial application is as a crucial building block for the production of a major class of insecticides, notably dimethoate and omethoate. These systemic and contact insecticides are widely used in agriculture to control a broad spectrum of sucking and chewing insects on various crops. The compound serves as the phosphorothioate core structure in these final active ingredients. As a reactive organophosphorus synthon, it is also utilized in organic synthesis and materials chemistry research. It is important to handle this chemical with appropriate safety precautions due to the general toxicity associated with organophosphorus compounds and its role as a pesticide precursor.