This report describes by the first time the use of a commercial screen-printed carbon electrode modified with multi-walled carbon nanotubes for voltammetric determination of the fungicide carbendazim in the presence of an anionic surfactant. The oxidation of the pesticide showed two anodic and two catodic peaks over a quasi-reversible system. The quantitative studies were performed using square-wave voltammetry technique at anodic direction, in that an oxidation peak was observed at +0.98 V vs. Ag/AgCl. Buffer, pH and voltammetric parameters were investigated and optimized. The use of the anionic surfactant sodium dodecyl sulphate provided a significative improvement on analytical sensitivity and its influence also was evaluated. The best conditions for analysis were achieved using a medium of 0.04 mol L−1 Britton-Robinson buffer at pH 4.00 containing 6.04×10−4 mol L−1 of surfactant. A calibration curve with good linearity (R=0.999) was obtained and the limit of detection achieved was 1.40×10−8 mol L−1 (2.7 ppb). Lastly, the developed method was successfully applied for determination of carbendazim in a spiked orange juice sample and a recovery of 101.7 % was obtained. The results were compared with HPLC technique with good agreement. Based on the data presented, the proposed method shows great promise to be applied in routine analysis of carbendazim in food samples and the approach based on the anionic surfactant effect can be an improvement for other applications.