Azinphos-ethyl concentrations in the blood, urine, and gastric lavage liquid from medical examiner cases are reported. In all cases, there was ingestion of the organophosphate pesticide. They are presented under three categories of intoxication: less serious, more serious, and fatal intoxications. The results of this study indicate that it was not possible to determine the blood levels that show the correct degree of intoxication and of lethal dose. Fast methods are given for identification and quantification of azinphos-ethyl in human biological fluids.