Atrazine-imprinted microspheres were prepared using a microfluidic device. With a dispersed phase containing atrazine, methacrylic acid, ethylene glycol dimethacrylate, and 2,2-azobis(2,4-dimethylvaleronitrile) and a continuous phase containing poly(vinyl alcohol), droplets could be generated by shearing force of continuous phase in a Y-junction microfluidic device. Monodisperse droplets were polymerized by UV irradiation to yield the imprinted polymer that showed selective binding for atrazine.