Iron proteinates (metalosates) are very effective preparations for the treatment of acute and chronic iron deficiencies in animals. A technology for the production of iron proteinate was elaborated employing waste-whey proteins. The iron content in the preparation could be varied by altering the pH and the amount of precipitating agent (FeSO4). The formation of iron proteinate was proved by infrared spectra. The absorbance of both C-N (1520 cm-1 and 1630 cm-1) and of C-O stretchings (1100 cm-1) indicated the presence of chelate bonds typical of an iron-proteinate molecule. The biological activity of the product obtained was tested on piglets. Preliminary results showed a good effect both on the animal body weight and on the blood indices, after oral application.