Young, uncastrated male cattle (initial weight 80 kg, final weight 240 kg) were used to evaluate brewers' dried grains as a protein source (17 or 36% of the concentrate mixture), in comparison with soyabean oil meal (6% of the concentrate mixture). There were no significant effects on feed intake or average daily live-weight gain. The killing-out percentages for the three treatments were 49·2; 48·6 and 46·9 respectively (P < 0·001). There was a lower fat deposition (P < 0·01) in animals receiving the higher level of brewers' dried grains, and the degree of rumen parakeratosis was less (P < 0·001) with the diets containing grains.