Nerve agents and pesticides belong to the group of organophosphates. They are able to inhibit irreversibly the enzyme acetylcholinesterase (AChE). Acetylcholinesterase reactivators were designed for the treatment of nerve agent intoxications. Their potency to reactivate pesticide-inhibited AChE was many times evaluated. In this study, five commonly used AChE reactivators (pralidoxime, methoxime, HI-6, obidoxime, trimedoxime) for the reactivation of AChE inhibited by two pesticides (chlorpyrifos and methylchlorpyrifos) were used. Russian VX (nerve agent) as a member of nerve agents' family was taken for comparison. Obtained results show that oximes developed against nerve agent intoxication are less effective for intoxication with organophosphorus pesticides. Especially, methylchlorpyrifos-inhibited AChE was found to be poorly reactivated by the compounds used.