Multiple liver metastases were incidentally detected in the lobe of the liver of an 81-year-old woman following total thyroidectomy and ablative radioactive iodine administration for the treatment of papillary thyroid carcinoma. A biopsy specimen taken from the metastatic liver tumor was histologically diagnosed as anaplastic carcinoma. Immunohistochemical staining for p53 was positive in both the primary tumor and liver biopsy specimens. We considered this to have been caused by anaplastic transformation from papillary thyroid carcinoma during treatment. We report a rare case of multiple liver metastases from a papillary thyroid carcinoma, which we believe to be the result of anaplastic transformation during postoperative radioactive iodine-131 therapy.