The author studied the effect of pyridine-2-aldoxime methiodide (PAM) on various alkylphosphate poisoning from the standpoints of (1) its effect on LD(50) in mice; (2) on the recovery of blood cholinesterase (ChE) in rabbits; and (3) on human cases. 1. The effectiveness of PAM against Ethyl- and Methyl- parathion was already established in human by Hiraki et al. The auther carried on animal experiments and ascertained the effectiveness. 2. In the cases of EPN and Diazinon poisoning PAM proves to be effective both in human and animals. 3. As for TEPP, Pestox-3, Malathon, Dipterex, and DFP, it was impossible to encounter human cases, but in animal experiments with these alkylphospnates PAM seems to be also effective. Therefore, PAM is to be applied for these alkylphosphate poisoning in human.