Methamidophos, trade name "Monitor," is an organophosphate insecticide.

Crops grown with the use of methamidophos include potatoes and some Latin American rice Many nations have used methamidophos on crops, including developed nations such as Spain, United States, Japan, and Australia. Due to its toxicity, the use of pesticides that contain methamidophos is currently being phased out in Brazil. In 2009, all uses in the United States were voluntarily canceled.