The production of n-butanol by fermentation of hydrolysates of Pinus radiata, using Clostridium acetobutylicum, has been investigated. Attempts to ferment the crude hydrolysate were unsuccessful. Pre-treatment of the hydrolysate by steam stripping followed by addition of activated carbon led to successful fermentation, but the treatment procedure caused unacceptable sugar losses. An alternative pre-treatment procedure using anion and cation exchange resins caused no such losses, and gave a butanol concentration after fermentation of 5·7 g/l, representing a yield of 17% based on sugar utilised.