Investigations were conducted to test the suitability of porous cups for sampling soil water to determine pesticides. Pesticide contents were controlled over a sampling period in an aqueous medium containing soluble organic matter and in a soil medium treated with atrazine or isoproturon both 14C-labelled. The tests proved that the disturbance of pesticide concentration in the extracted water concerned only the first volume extracted (fifty milliliters). Thus, the resulting 500 ml sample had a herbicide content close to that of the corresponding leachate. The system still worked well after a dessication period or a simulated rainfall. These results confirmed clearly the usefulness of porous cups for pesticide monitoring campaigns provided the samples volume is superior to 50 ml.