The effectiveness of aqueous solutions of sodium chloride and potassium chloride as wood preservatives was tested against larvae of the house longhorn beetle Hylotrupes bajulus (L.). Immersion of pine (Pinus sylvestris L.) blocks for 24 h provided only a shallow protective layer. In a test series according to EN 46 a concentration of 200 g litre-1 potassium chloride was required for complete larval mortality within 12 weeks; 200 g litre-1 sodium chloride failed to achieve this. With vacuum impregnation in tests according to EN 47 a concentration of 100 g litre-1 sodium chloride achieved complete mortality of larvae within four weeks. Vacuum impregnation of 100 g litre-1 potassium chloride attained complete mortality only after 12 weeks. Ovipositing female beetles did not avoid wooden blocks treated with either salt. © 1997 SCI.