Current suggestions for the upper limit for the total gucosinolate content of oilseed rape are around 20 μmol/g of seed, which corresponds to a level in the de-fatted meal of approximately 33 μ mol/g. Information about the suitability of this material for incorporation in growing pig diets is required by the UK feed industry. When attempting to provide the required information the presence of factors such as tannins, sinapine and phytate in rapeseed meal should be considered, as must the high (≈ 120 g/kg) fibre content of the material. This experiment was designed to examine growing pig performance from 30 to 75 kg liveweight when fed diets containing increasing levels of rapeseed meal at both fixed and increasing glucosinolate contents.