The aim of our research was to determine the influence of the soil type and adjuvants on the dynamics of ethofumesate degradation in soil. Samples of two types of soil were placed in growth chambers. Ethofumesate was applied at a rate of 800 g·ha^-1, alone and in mixture with adjuvant based on methylated crop oil and surfactant adjuvant. Residues of ethofumesate were determined using high-performance liquid chromatography with UV detection. The type of soil influenced the degradation rate of ethofumesate. Significant differences in degradation rate between soils during the first period after treatment (36 days) influenced the DT₅₀ indicator. The addition of oil adjuvant slowed down the degradation of ethofumesate and increased the level of residue in soils. The DT₅₀ value for mixture ethofumesate + oil adjuvant was about 8-10 days higher in comparison with the DT₅₀ for ethofumesate applied alone. No significant differences were observed between degradation rates and the DT₅₀ for ethofumesate applied alone and with surfactant adjuvant.