Azamethiphos is an organothiophosphate insecticide. It is a veterinary drug used in Atlantic salmon fish farming along with other fish in the Salmonid family to control parasites, specifically sea lice. It is also used as an insecticide in biocidal products in Europe.

Organophosphorus insecticides such as azamethiphos inhibit the action of the enzyme acetylcholinesterase. The acetylcholine, therefore, remains intact allowing the electrical signal to proceed without interruption. This phenomenon leads to overexcitation of the organism and eventually to the death of the insect.

Azamethiphos penetrates through the cuticle or through the cuticle opening of the insect, and also acts by ingestion and absorption through the digestive system.

In Europe, azamethiphos is an active substance, according to the Biocide Regulation 528/2012, to be used as an insecticide.

It is used in several biocidal products in Europe, such as insecticides, mainly for professional users. It is commonly used against flies in animal housing.

Azamethiphos is sensitive to hydrolysis, especially at low pH.

Azamethiphos is of moderate acute oral toxicity with LD₅₀ values ranging from 834 mg/kg in the rat to 1764 mg/kg in the hamster. Acute dermal toxicity is very low; LD₅₀ values of >2020 and >6000 mg/kg are reported in the rabbit and an LD₅₀ of >2150 mg/kg is reported in the rat.

Azamethiphos is an irritant to the eyes and skin. It is considered toxic if inhaled and is harmful if swallowed. It is also believed to be a possible carcinogen and can cause damage to organs.