Passive samplers can integrate fluctuating concentrations of organic micropollutants in the aquatic environment, and allow the determination of reliable estimates of average concentrations. In agricultural watersheds, most passive samplers cannot however integrate high and transient concentrations of pesticides in small rivers. Passive stir bar sorptive extraction (SBSE) is a novel and simple passive sampling technique suited for highly fluctuating micropollutant concentrations. The aim of this study was to evaluate, under controlled laboratory conditions, the response of SBSE stir bars exposed first to concentration peaks, then to low concentrations of 20 pesticides. Results show that passive SBSE allows a fast integration of the concentration peaks of the pesticides. Also, large to no elimination of the pesticides were observed for the SBSE stir bars plunged in unspiked water, whereas partial elimination to additional accumulation were observed for the SBSE stir bars plunged in spiked water. These results provide a clear insight on the behavior of passive SBSE during concentration peaks of the pesticides and its potential performances during field applications.