Clavulanic acid is a Beta-lactam antibiotic produced by Streptomyces clavuligerus. In this investigation, effect of rapeseed oil and soybean oil on the antibiotic production was studied. The amount of 0.1 – 20 g/l of the oils was supplemented to the basal fermentation media, which were containing malt (medium 1) and malt + dextrin (medium 2) as carbon sources. Maximum concentration of clavulanic acid was obtained in the media supplemented by 0.25 g/l rapeseed oil and 0.5 g/l soya oil. Enhancing effect of the oils was seen in the media containing up to 1 g/l of the oils. However, concentration of clavulanic acid was decreased in the media containing more than 1 g/l of the oils.