The control of environmental pollution has demanded increasingly determination of sulphur in a variety of matrices. Different analytical methods have been developed for the determination of this analyte in biodiesel fuel using various analytical techniques, including spectroanalytic and chromatographic methods. In this work a square-wave cathodic adsorptive stripping voltammetric (SW-AdCSV) procedure is proposed for the determination of sulphur in biodiesel, using a glassy carbon electrode modified with mercury-film (MFE). A buffer solution containing sodium acetate 1.4 mol L-1 and acetic acid 2% was used as supporting electrolyte in two different media (methanol an propanol). The voltammetric measurements were performed adding 70 mu L of biodiesel sample previously treated with tetramethylammonium hydroxide (TMAH) to the supporting electrolyte. The method showed good linearity (r = 0.998) in the determination of sulphur in biodiesel (medium-concentration of 2.68 x 10(-8) mol L-1 (1.07 x 10(-3) mg kg(-1)) for a confidential level of 95%. Low values of limit of detection-LOD (3.29 x 10 (-10) mol L-1 (1.32 x 10(-5) mg kg(-1)) and limit of quantification-LOQ (1.10x10(- 9) mol L-1 (4.40 x 10(-5) mg kg(-1)) indicate a good sensitivity of the method. A validation of the procedure was carried out by comparing this procedure with the results obtained by an official method, using the same sample, through Teste-t of Student (confidence level of 95%). These results indicated that both methods are statistically equivalent, thus demonstrating the feasibility of the new method. (C) 2017 Elsevier Ltd. All rights reserved.