To evaluate nutritional effects induced in calves by feeding soybean trypsin inhibitor, 16 calves were fed 1) raw soybeans, 2) heated soybeans, 3) heated soybeans plus soybean trypsin inhibitor, 4) heated (raw soybeans plus soybean trypsin inhibitor). Ration 1 caused depression of growth and reduced digestibility of protein and fat as compared to Ration 2. No differences were significant in calves fed Rations 3 and 4. The weights and enzymatic activities of pancreas were similar in all groups. Soybean trypsin inhibitor plays a minor role, if any, in calf nutrition.