The aim of the study was to evaluate the movement and accumulation of 2,6 – dinitro – NN – dipropyl – 4 - trifluoromethylanil (trifluralin) in soil under irrigated conditions. Despite its hazardous effects this herbicide is widely used in the country. The herbicide researched, is known to be one of the most resistant and least mobile pesticides used in the country. The investigations were carried out, using drainage type lysimeters with application of two different doses of trifluralin and three irrigation water levels. Irrigations were applied during three stages used as indicators for irrigation scheduling of the sunflower crop. Disturbed and undisturbed soil samples were taken from the original field in the beginning and from the tanks after completing of the study. Trifluralin analyses were completed using gas chromatography technique. The results of the study determined that the amounts of the herbicide and its degradation product (2-ethyl-4-nitro-6-trifluoromethyl-1H-benzimidazole) in the ranges of 3.04 – 0.1 and 4.128- 0.344 ppm, respectively were accumulated in the lysimeter soils during the 5-year research period. The highest amounts of trifluralin and its degradation product were measured in the 0-30 cm soil layer, of the treatment with higher applied herbicide amount and deficit irrigation.