Hydrolysis of protein solid wastes from tanneries to yield protein meal for animal nutrition has been performed in a pilot assembly designed to process 400 kg h(-1) of disposal material under optimum energy consumption and product yield conditions. Evaluation of the significance of amino acid degradation caused by the process, in relation to the product cost and quality in animal nutrition, was the purpose. A nutrition bioassay was carried out to study the incidence of dietary substitution of the above protein meal for soybean meal on growth performance by early weaned piglets. The results show that degradation of serine, proline, arginine and threonine occurs during collagen hydrolysis, and that only the threonine concentration in the product falls below the dietary requirement. However, integration of protein meal diets with the necessary amino acid content may be accomplished cheaply. Compared with other vegetable and animal commercial protein meals, the cost of the product obtained from tanned hides appears competitive. Processing of other tannery disposal material is not recommended, due to the low protein content of the starting material.