Styrene sulphonic acid (SSA) doped polyaniline (PAni) was chemically synthesized. The synthesized product SSA-PAni was treated with 3-(aminopropyl) triethoxysilane in order to achieve a functional terminal of -NH2 group. This functional nanopolymer has been electrochemically deposited on to the working area of a carbon screen printed electrode (carbon SPE). Incubation of the SSA-PAni modified carbon SPE with anti-atrazine antibodies yielded the formation of a pesticide immunosensor. This immunosensor offered specific and highly sensitive detection (limit of detection 0.01 ng/mL) of atrazine over a wide concentration range (0.01-50 ng/mL). (C) 2014 Elsevier Ltd. All rights reserved.