Abstract: The invention relates to a process for the production of thyroglobulin, which is used in the treatment of hypothyroidism, from hog thyroid glands. Ground hog thyroid glands are subjected to saline digestion to produce a thyroglobulin extract. The extract is precipitated by pH adjustment and then heated to a denaturing temperature. The denatured precipitated thyroglobulin solution is subjected to a separation step to produce crude wet thyroglobulin solids. The crude thyroglobulin solids are defatted and dewatered by solvent extraction. The resultant defatted thyroglobulin product can then be further worked up, for example, by drying, milling, and screening, to produce a powdered product. In order to achieve a final product having a T.sub.4 /T.sub.3 ratio of 2.6-3.4 and upon proteolysis a minimum of 0.7 .mu.g/mg of levothyronine and 2.1 .mu.g/mg of liothyronine, the time periods for the precipitating, denaturing, and/or defatting steps are carefully controlled so that the T.sub.4 /T.sub.