Colorectal cancer (CRC) metastasis to the thyroid gland is rare. Here we report a 45 yr-old man in western Iran referred to Hematology Clinic, Kermanshah City, Iran in March 2014 with complaint of exertional dyspnea, multi-nodular goiter as well as complaint of exertional dyspnea, and multi-nodular goiter. His history included a low anterior resection of rectum in 9 months ago for a high-risk stage II rectal adenocarcinoma. He did not show clinical signs of hyperthyroidism other than thyroid enlargement. In thyroid nodule the FNA cytology, pathology reported anaplastic thyroid malignancy. Pathologists reported final diagnosis of colorectal metastasis of thyroid gland. Then due to metastatic pattern of disease, his pathology was evaluated for RAS molecular assay. In the patients of metastatic CRC, RAS testing is the first step to identify those patients that could benefit from anti-EGFR monoclonal antibodies treatment.