Lipase-mediated acrylation is an attractive alternative to more traditional chemical processes, since it provides specific catalysis under mild conditions. A detailed study of the effects of solvent choice and substrate concentrations on the acrylation of octanol by Candida antarctica lipase B (Novozym 435) is presented. Acrylic acid was found to have a pronounced inhibitory effect. Partial neutralisation of the acid substrate by addition of an organo-soluble base markedly altered the activity profile, indicating the inhibitory mechanism to be related to acid-base interactions. The concentration of acrylic acid to be employed was found to be important in the choice of an appropriate solvent. At low acrylic acid concentrations, the highest rates and conversions were obtained using hydrophobic solvents, whereas at higher acrylic acid concentrations more polar solvents were advantageous.