Effect of surfactants present in alkaline and acidic solutions on the capacitance of carbon electrodes has been studied. Three various types of surfactants, i.e. sodium dodecyl sulphate (SDS), tetrapropylammonium bromide (TPAB) and non-ionic such as polymer of polyethylene glycol and p-t-octylophenol (Triton X-100) have been selected for this target. Concentration of these electrolyte additives was 0.005 mol L-1. Decreasing the surface tension in the electrode/electrolyte interface allows better penetration of electrolyte into the pores. However, surfactants played a different role depending on the electrode polarity. Detailed analysis of capacitance versus current load, frequency dependence as well as self-discharge and cyclability proved especially a profitable effect of Triton X-100 on capacitor operating in alkaline solution. (C) 2010 Elsevier Ltd. All rights reserved.