The possibility of substituting maize for sorghum grain in fattening diets was studied in a digestibility trial with wethers and a growth study with steers. ln die digestibility trial a 6 x 6 Latin square design was used with maize, bird-resistant and non bird-resistant sorghum grain as energy sources and sunflower oil cake or urea as protein supplement. In the growth study diets in which maize was replaced by either 0, 33, 67 or l00% bird-resistant or non bird- resistant sorghum grain, were tested. In the mass interval 200 to 300 kg sunflower oil cake was used as protein supplement and between 300 and 400 kg, urea. All diets were supplied in the ground form. Apparent DOM did not differ significantly between the maize and non bird-resistant sorghum grain treatments, while the bird-resistant sorghum grain treatments were highly significantly lower. Similar results were obtained with regard to apparent DCP and N-retention although the percentage reduction in apparent DCP for bird-resistant sorghum grain was proportionally more drastic than in the case of apparent DOM. In the growth study there were no significant differences between the maize and non bird-resistant sorghum grain treatments in intake, gain, kg feed/kg live mass or kg feed/kg carcass mass produced. The bird-resistant grain sorghum realized a highly significantly (p<0,01) higher intake. Protein supplement did not have a significant differential effect in either the digestibility trial or the growth study.