Eight different roughages (clover grass silage, 2 samples of fresh clover grass, fresh ryegrass, winter wheat whole crop silage, pea whole crop silage, dried grass and goats rue) were examined for effective degradability in the rumen and total tract digestibility of individual amino acids (AA), total AA and crude protein using in situ method. Effective degradabilities calculated at a rumen fractional outflow rate of 5%/h, were higher for crude protein than for total AA (the differences ranging from 1.9 to 4.1 percentage points). Arginine was the least degradable amino acid, particularly in silage and in short rumen incubations, although cysteine and phenylalanine also tended to be less degraded than total AA. The most degradable amino acids were alanine and proline in silages, and cysteine, aspartic acid and glutamic acid in the other roughages. Disappearance of total AA from mobile bags containing samples of feeds after 16 h preincubation in the rumen varied from 79.8% in dried grass to 95.9% in fresh clover grass, and was generally similar to the disappearance of crude protein, 79.7-96.3%, respectively. In most of the examined roughages, cystine and glycine disappeared the least, and glutamic acid, aspartic acid and alanine the most from mobile bags, as compared with total AA.