Two cases of parenteral injection of organophosphate insecticide are reported. A 20-year-old man injected himself malathion intramuscularly. The developed necrosis in the injection set and abscess formation, and developed a severe poisoning reaction of late onset that was fully manifested 60 hours after the injection. A 22-year-old girl injected herself subcutaneously a small amount of fenitrothion and had severe swelling of the affected limb and a sterile abscess.