A fifty-years old man underwent Miles’ operation (abdomino- perineal resection) for a rectal carcinoma seven years ago. The follow-up examinations had been normal for seven years. A new thyroid nodule developed, and serum carcinoembryonic antigen level was found to be elevated during the last follow-up examination. Total thyroidectomy was performed since the fine-needle aspiration from the nodule in thyroid gland revealed malignant cells, but it was difficult to distinguish metastatic thyroid cancer from this primary one. Pathological examination of thyroidectomy specimen revealed a metastasis to both lobes of thyroid gland, and the nodule in thyroid gland was differentiated papillary carcinoma of thyroid. The present patient is the first example of colorectal carcinoma metastasizing to the thyroid gland which has also differentiated papillary carcinoma. [Turk J Cancer 2008;38(3):142-144]