Accurate and precise voltammetric method has been developed and validated for quantitative determination of entacapone in bulk, pharmaceutical dosage forms and human plasma at carbon paste electrode in Britton-Robinson buffer of pH range (2-10) in presence of Triton X-100. Several factors such as pH, type of surfactant, scan rate and accumulation time were investigated in order to study the optimum conditions for determination of entacapone. A good linear relationship was obtained within the concentration range from 1.0 x 10(-6) to 3.8 x 10(-5) mol L-1 with mean recovery and relative standard deviation values of 100.26% and 1.72%, respectively. The limits of detection and quantification were found to be 1.13 x 10(-7) and 3.76 x 10(-7) mol L-1, respectively. The obtained results are in good agreement with those obtained by a reference method. The proposed method is simple, rapid and economic, so it is suitable for routine analysis of entacapone in pure form and dosage forms and for pharmacokinetic studies. (C) 2015 Elsevier B.V. All rights reserved.