1. A study was conducted to compare apparent and true digestibility of amino acids in a high protein experimental diet between young ostriches (7 months of age) and cockerels. 2. A mean value for true digestibility of amino acids (TAAD) of 0.837 +/- 0.0073 (range 0.780 to 0.862) was derived for ostriches, compared with a mean value of 0.795 +/- 0.0258 (range 0.723 to 0.825) for cockerels. 3. True retention of dietary protein was 0.646 +/- 0.0114 and 0.609 +/- 0.0643 for ostriches and cockerels respectively. 4. Results in the present study produced evidence that the method for determining metabolisable energy values of ingredients for ostriches is also suitable for measuring the digestibility of amino acids. 5. It was concluded that accurate diet formulation for ostriches requires the assessment of amino acid digestibilities for individual ingredients, because values derived from poultry would underestimate digestibilities for ostriches.