Thyroid lipomatosis is a rare disease, characterized by diffuse infiltration of the stroma by mature adipose tissue, leading to increased size of thyroid gland. The pathophysiology of diffuse proliferation of adipose tissue in the thyroid gland is unclear. Our study involves 2 cases with thyroid lipomatosis treated in surgical department B, Ibn Sina University Hospital. In the 2 cases studied, the average age was 50 years and the 2 patients were female. The 2 patients had consulted for a cervical swelling and the physical examination had found a goiter in both patients. They were treated with total thyroidectomy, and the postoperative follow-up was simple, with no deplorable complications. Pathological examination of the surgical specimen showed infiltration of the entire thyroid parenchyma by mature adipocytes, without any sign of hyperplasia, malignancy or amyloid deposition. Diffuse thyroid lipomatosis is considered a rare condition with about 20 cases described in the literature. This entity has no malignant evolutionary potential and the complications are of a mechanical nature.