The toxicity of a number of orchard pesticides to the predatory mitesAmblyseius fallacis(Garman), andTyphlodromus pyriScheuten, was determined in the laboratory by use of the standard slide-dip technique. Results indicated that azinphosmethyl and endosulfan were non-toxic to both species. Chloropropylate, formetanate hydrochloride, dimethoate and Galecron, however, were extremely toxic to the species. Carbaryl, demeton, and phosalone were highly toxic toA. fallacis, but these materials were nontoxic toT. pyri. Several other pesticides exhibited either no, slight, or moderate toxic effect onA. fallacisandT. pyri. Use of these materials in an integrated pest control program may allow predators to persist in apple orchards and provide satisfactory regulation of phytophagous mites at economic levels.