Abstract: The thyroid gland in most animal species has two lobes, one on each lateral surface of the trachea. In pigs, the main lobe of the thyroid gland is on the midline in the ventral cervical region with dorsolateral projections from each side. The thyroid structural changes in gouts were investigated. About 386 pairs of thyroid glands collected from gout at the local municipal abattoir in Tabriz city of East Azerbaijan province. A total of 386 thyroid specimens examined, 8 cases were follicular atrophy, 4 cases were thyroid fibrosis, 71 cases were diffuse hyperplasia of thyroid follicular cells, 5 cases were colloid goiter, 10 cases were parenchymal cysts, 3 cases were nodular hyperplasia, 1 case was C-cell adenoma and 1 case was C-cell carcinoma.