Chlorpyrifos (CPF) is a broad spectrum organophosphate pesticide. Organophosphate pesticides comprise a group of substances used in agriculture for insect and plague control, infestations in buildings, man or domestic animals. The use of insecticides represents an environmental risk due to the high mass of product applied annually. This book discusses the toxicological properties, uses and effects on human health and environment of the organophosphate pesticide, chlorpyrifos.