The objective of the present work is to determine sorption coefficients of the herbicide imazaquin using the differential pulse polarography in the major soil classes occurring in the State of São Paulo, Brazil. This study contributes to the predictions of pesticide fate and transport mechanisms in the environment as well as its exposure and interactions with different soil materials. Imazaquin was analysed directly in soil samples (scan rate 2 mV s^-1, mercury drop size 0.37 mm, and pulse height 50 mV) and the detection limits varied from 42 to 58 g L^-1 for different soils. Imazaquin showed the K values varying from 0.8 (for the sandy soil) to 35.5 L kg^-1 (for the medium textured soil), with a significant dependence on the soil pH, organic matter content, and clay minerals. The study demonstrates the practical utilisation of the electroanalytical methodology to determine the imazaquin adsorption in soil and consequently assess the impact of this herbicide in the environment, especially for the evaluation of the potential risk of surface and groundwater contamination.