Mixtures of volatile reduced sulphur compounds (VRSCs) like hydrogen sulphide (H2S), methylmercaptan (MM), dimethyl sulphide (DMS) and dimethyl disulphide (DMDS) are found in gaseous emissions of several industrial activities creating nuisance in the surroundings. Hydrogen sulphide (H2S) decreases the removal efficiency of volatile reduced sulphur compounds (VRSCs) in biofilters but the kinetics of this effect is still unknown. Kinetic expressions that represent the rate of bio-oxidation of H2S, MM, DMS and DMDS are proposed. In order to observe and quantify this effect, equimolar mixtures of MM. DMS and DMDS were fed into a biotrickling filter inoculated with Thiobacillus thioparus at different H2S loads. Experimental results shown a good agreement with the simulations generated by the model considering the kinetic equations proposed. The estimated kinetic constants show that H2S and MM have a significant inhibitory effect on the bio-oxidation of DMS and DMDS, having the H2S the higher effect. (C) 2012 Elsevier Ltd. All rights reserved.