On the basis of microbiological tests of natural and synthetic adhesives two fungi-and bactericides, dichlorophen and 4-chlor-3-cresol, were selected. It was found that bacteria, particularly spore-forming ones, were much harder to kill and that experimental biocides acted merely bacteriostatic. Dichlorophen was slightly more effective than 4-chlor-3-cresol. The standardization of microbioresistance of adhesives, used in archive and library materials conservation, considering the measurement of viscosity and microbiological analysis has been proposed. Author's address: Institute of Industrial Organic Chemistry Annopol 6, Warsaw, Poland.