Seven batches of maize gluten feed (MGF) were studied for their protein and amino acid standardised ileal digestibility (SID). Each batch was tested on four castrated male pigs Large White (LW) or (LW x Landrace - L) x (LW x Piétrain - P) weighing between 42 and 61 kg, and fitted with an end-to-end ileo-rectal anastomosis. In all batches, lysine, threonine, cystine, tryptophan, aspartic acid and glycine displayed the lowest SID values (on average 62.9, 69.6, 66.7, 64.1, 69.7 and 62.4%, respectively). On the contrary, methionine, arginine, leucine, tyrosine and phenylalanine were among the most digestible amino acids and their average SID reached 84.8, 85.6, 82.3, 83.2 and 82.7%, respectively. Significant differences between batches of MGF appeared for SID of most amino acids. SID of most amino acids decreased as the proportion of N bound to the NDF residue increased.