Recoveries of Sevin® (1-naphthyl N -methylcarbamate), Kepone® (decachlorooctahydro-1,3,4-metheno-21f-cyclobuta [ed] pentalen-2-one), Bayer 29493 ( O,O -dimethyl O -[4-(methylthio)- m -tolyl] phosphorothioate), Bayer 22408 ( O -naphthalimido- O,O -diethyl phosphorothioate), Ruelene® ( O -4-tert-butyl-2-chlorophenyl O -methyl methylphosphoramidate), and CoRal® ( O,O -diethyI O -(3-ch loro-4-methylumbelliferonc) phosphorothioate) from milk ranged from 87% to 97% using acetonitrile and chloroform as the primary extraction solvents and acetonitrile- N -hexane as a cleanup procedure. This extraction procedure was somewhat less effective for removing known amounts of DDT and dieldrin from milk. Acetonitrile-chloroform extraction of milk was usually more efficient for removing insecticides than was a 2: 1 mixture of diethyl ether and N -hexane. Ruelene, Bayer 22408, and Bayer 29493 were stable In Vitro in raw milk for periods up to 14 days of incubation, but after 3 days incubation, some Co-Ral equivalents remained in the milk residue following acetonitrile-chloroform extraction.