Abstract Bis-quaternary ammonium and bis-imidazolium chlorides, the compounds containing in their structure two symmetrical quaternary nitrogen atoms, were prepared and tested on wood destroying and sapstaining fungi. The effect of the position of quaternary nitrogen atoms upon fungicidal and surface properties was analysed. The antifungal activity of new bis-quaternary ammonium and bis-imidazolium chlorides against Coniophora puteana (Schum.:Fr.)Kr., Trametes versicolor (L.:Fr.)Pilát and Aspergillus niger van Tieghem was much more pronounced than that of quaternary ammonium chlorides. The results confirm the correlation between surface activity and fungicidal activity. The adsorption of bisimidazolium chloride onto pine wood was influenced by pH of applied solutions and the initial solution concentration. With increasing pH of ammonium solution, the adsorption was much greater than in neutral or acidic solutions. Cation structure of the quaternary ammonium chloride exerted a strong influence on quantity of wood-adsorbed chemicals and resistance to water leaching.