ABSTEACT: An aqueous solution of indoxacarb pesticide was sent to rats by the Peroz method at a dose of 1/10 LD50 once via zond and the amount of residual pesticides in the rat was determined at 5, 10, 20, 30, 40 days after poisoning. For the analysis of residual pesticide quantities, the HPLC MS (6420) Tripl Quad LC/MS (Agilent Ttchnologies, USA) device was used. As a method of ionization, APCI(Atmospheric pressure chemical ionization) method was used.