Adsorption of atrazine on nanoporous polymeric adsorbents, PAD 400 and PAD 610, was investigated. The effect of particle size, pH, ionic strength, and temperature along with kinetic, equilibrium, and thermodynamic studies reveal the efficiency of PAD 400 with a higher adsorption capacity than PAD 610. The equilibrium data obey the Freundlich isotherm and the kinetic data were well described by the pseudo-second-order model. Spontaneous, endothermic, and random characteristics of the process were confirmed by thermodynamic analysis.