A new approach for photoelectrocatalytic determination of sulphide in a flow injection analysis (FIA) system was studied using a poly-methylene blue modified glassy carbon electrode (poly-MB/GCE). Results from electrochemical measurements have revealed that poly-MB/GCE is capable of signalling electrocatalytic and photoelectrocatalytic activity towards sulphide oxidation. When the surface of poly-MB/GCE was irradiated with a light source (250W Halogen lamp), the electrocatalytic current increased substantially. A homemade flow electrochemical cell with a suitable transparent window for the irradiation of the electrode surface was used to perform the photoelectrocatalytic determination of sulphide in FIA system. The currents obtained from the photoamperometric measurements in the FIA system at optimum conditions (carrier solution: pH 9.0 Britton Robinson buffer solution containing 0.1 M KCl; flow rate: 1.3 mL min(-1); transmission tubing length: 10 cm; injection volume: 100 mu L; and constant applied potential: +150 mV vs. Ag/AgCl/KClcat) were linearly correlated with the sulphide concentration. The calibration curves were obtained for sulphide concentrations in a range of 0.5-500 mu M. The detection limits were found to be 0.27 and 0.15 mu M for amperometric and photoamperometric methods, respectively. The proposed method was successfully applied to different wastewaters such as municipal sewage or tannery wastewater. Finally, results from the sulphide measurements by poly-MB/GCE were in good agreement with those attained using spectrophotometric method. Clown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.