A polyaniline-multi-walled carbon nanotubes (PANI-MWCNTs) composite modified electrode was fabricated and the electrochemical behaviors of acetaminophen on the PANI-MWCNTs composite modified electrode were investigated by using cyclic voltammetry (CV), single-potential step chronocoulometry and square-wave voltammetry (SWV). The results showed that this electrode exhibited excellent electrocatalytic effects on the redox of acetaminophen. Consequently, a simple and sensitive electroanalytical method was developed for the determination of acetaminophen. The oxidation peak current was proportional to the concentration of acetaminophen from 1.0 X 10(-6) to 1.0 X 10(-4) mol/L and 2.5 x 10(-4) to 2.0 x 10(-3) mol/L, respectively. The detection limit was 2.5 x 10(-7) mol/L. The proposed method was used to detect acetaminophen in Composite Chlorzoxazone Tablets and the results were satisfying. (c) 2006 Elsevier Ltd. All rights reserved.